Has anyone come up with a method that allows people to take pictures with a regular digital camera and then download them wirelessly to a computer, and/or perhaps to the Internet?

There have been a few digital cameras with built-in Wi-Fi wireless capability, but the best and simplest method I know is a $100 product called Eye-Fi. This tiny gadget looks and works like a regular, garden-variety SD memory card, but it packs a Wi-Fi transmitter inside. It fits into a standard SD memory-card slot and is compatible with a wide range of camera models from Canon (CAJ), Kodak (EK), Nikon (NINOF.PK) and others.

Coupled with clever software, and a clever Web site, the Eye-Fi card automatically zips your pictures wirelessly to your PC or Mac, and/or to your choice of over 20 online photo-sharing services.

For more information, see www.eye.fi. For a list of compatible cameras, see support.eye.fi/compatibility/. For a full review of the product, see: solution.allthingsd.com/20071121/.

You mentioned last week that SugarSync might be a good solution for backups, so if one computer dies your files still exist on another system. But what if the doomed computer doesn’t actually die but its files are corrupted by malicious software? Do those newly corrupted files overwrite the good copies on your SugarSync network?

They could do so, depending on which folders you had chosen to replicate on your other computers. Automatic-synchronization services like SugarSync have a tough time telling whether changes to a file are deliberate, accidental or the result of some sort of corruption. Though the last is rare, it could look to SugarSync like you had changed the file on purpose.

One way to guard against that is for a service to offer “versioning” — the practice of maintaining multiple past copies of a file. That way, if a change isn’t intentional, you can go back to the prior, pristine version. Sharpcast, the company that makes SugarSync, says it is planning to add versioning to the service, but offers no specific date. In the meantime, one way to back up a file without fear of its being overwritten by a corrupted version is to upload it to SugarSync’s special “Web Archive” folder, whose contents are never automatically updated.

Have you ever reviewed and suggested a media player for connecting to a home theater to play all songs, videos and photos that exist on your home computers?

Yes, I have reviewed several over the years. The one I find simplest and best designed is Apple TV, which, despite its name, can work fine in a household with no other Apple (AAPL) hardware. It costs $229 and is a small, thin, unobtrusive box that fetches music, photos and videos from your home network using either a wired or a wireless connection. It can connect to your TV set or home theater via a variety of analog and digital ports, including component-video, HDMI, and optical and analog audio. It supports high-definition video and works with any computer, Windows or Mac, that has Apple’s free iTunes software installed and running.

Apple TV handles many standard photo, music and video formats, but it is limited to music and video files that iTunes can handle. That excludes copy-protected files in Microsoft’s formats, and certain open Microsoft formats, but includes common files like MP3s. Apple TV also allows you to access YouTube and to purchase music and TV shows from Apple, and rent movies from Apple, without the use of a computer.

• You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital Web site, http://walt.allthingsd.com.

On TV, they announced a $40 government-issued coupon that is available to offset some of the cost of the new digital converter boxes we will need for our older television sets. How do I go about getting some?

You can apply for a coupon at a federal government Web site designed expressly for that purpose: www.dtv2009.gov. Or, you can call 1-888-DTV-2009 (1-888-388-2009). Each household can receive up to two of the $40 coupons, which look like plastic gift cards, but they can’t be combined to purchase a single converter box. Each coupon must be applied to the purchase of a separate box, which the government estimates will cost between $50 and $70 at popular electronics stores. Coupons also must be used within 90 days of the date on which they are mailed to the consumer.

Note that these converter boxes won’t be needed for about a year, and aren’t necessary for TV sets containing digital tuners, also called an “ATSC” tuner. Such tuners have been included in many TV sets sold in the U.S. since 2004, even if they aren’t high definition televisions. Converter boxes also aren’t needed for older analog TV sets that receive their programs via cable or satellite services or other pay services. They are needed only for older analog TV sets that depend on free, over-the-air programming, the kind usually received via an indoor or outdoor antenna.

Is it possible to transfer data from a computer with Windows 95 to a computer which uses Windows XP?

Yes, but the trick would be to figure out a medium for the transfer. Many, if not most, Windows 95 PCs don’t have USB ports, which rules out using a USB thumb drive or external USB hard disk as the transfer mechanism. If your old PC can burn CDs, that might be a good way to transfer your data.

Another option is buying a program like LapLink’s PCMover, which explicitly supports Windows 95 and can automate the process using either a network, removable media, or parallel cables. See laplink.com for details.

I’m thinking of getting an iPod Touch to replace both my iPod shuffle and Palm Pilot Vx. Does the Touch have as good address book and to-do functions as the Palm has? Does the Touch sync to the Mac’s Address Book, Mail, and Calendar software? If so, would it also sync to a Windows box?

The iPod Touch, and its close cousin, the iPhone, do have what I consider to be a very good address book, or Contacts program, though it may not have all the same features you use on your Palm. And that address book can be easily synchronized with a computer.

On a Mac, the iPhone and Touch Contacts can be synced with the built-in Address Book, or with Entourage, Microsoft’s Outlook equivalent. On a Windows PC, it can be synced with Microsoft’s Outlook; with Outlook Express (Windows Address Book) in Windows XP; or with Windows Contacts in Windows Vista.

The calendar on the Touch and iPhone can be synchronized with the Mac’s built-in calendar, with the calendar in Entourage, and with the calendar in Outlook on a Windows PC.

However, neither the Touch nor the iPhone includes a true to-do or task function, and neither synchronizes email with a computer. They do have a good email program, but it is intended to work on its own, fetching and sending email directly, rather than copying email from a computer.

You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital Web site, http://walt.allthingsd.com.

We need a new DVD player but are completely confused about the Blu-Ray versus HD DVD war. We want to purchase something that will last us many years, but I’m afraid to splurge on it when it’s still unclear what the preferred format will be. One option looks to be buying a DVD player that can “upscale” to high definition. How much worse is this in terms of quality?

The good news is that the war appears to be winding down. Because I never saw any significant quality difference between the two high-definition formats, I never recommended one over the other. But most of the major studios have defected to Blu-Ray, so industry experts believe HD DVD is likely to recede as a movie format, though it may find a market as a data format for computers. However, the companies backing HD DVD haven’t given up, so the battle isn’t formally over.

Meanwhile, I have found that, for everyone but videophiles, “upscaling” DVD players are effective at making most regular DVDs look better on high-definition TV sets. And name-brand models can be found for as little as $45, which is less than Blu-Ray players are likely to commonly cost for quite awhile.

In your review of the new MacBook Air laptop, you said it lacked a wired Internet jack but that Apple plans to sell an adapter. Did you test this? When will it be available? And is there any way to use the MacBook Air with a cellphone network for Internet access?

Apple says the $30 wired Internet adapter will ship when the laptop does. I tested an early unit and found it worked fine. As for working on the cellphone data networks, you can use a cellphone modem from one of the network operators that connects via USB instead of a card slot. Unfortunately, I tested one of these, the Novatel USB727 from Verizon, and found that it was too wide to fit in the cramped space around the MacBook Air’s USB adapter. So you will need an extension cable, making for an ungainly attachment.

There are two other options. If you already own a cellphone data modem meant to fit a PC Card or ExpressCard slot, you can buy an adapter that allows these cards to work via a USB port. I tested such an adapter, a $40 model from a company called Siig that allowed me to use my older Novatel V640 ExpressCard modem with the MacBook Air. It worked well but is relatively large and is attached by a cable, so it is also bulky and ungainly.

The final option would be to pair the MacBook Air with a Bluetooth-equipped cellphone that is able to act as a wireless modem. No cables are required for this, but there is some setup. Ironically, one of the phones that lacks this capability is Apple’s own iPhone.

What happened to the Tablet PC version of Windows? Since Vista has come out, I can’t find a Tablet edition.

Microsoft decided to drop the separate tablet edition it produced for Windows XP and build its capabilities into Vista. Unless you have the least expensive version of Vista, called Home Basic, the full Tablet PC capability should be usable on any tablet PC running Vista. But there’s no longer a specific edition labeled that way.

You can find Mossberg’s Mailbox, and my other columns, online free at the new All Things Digital Web site, http://walt.allthingsd.com.

I currently spend about $50 to $60 per year for Norton Security software. Is this necessary when Windows XP has its own security built into the operating system?

Windows XP doesn’t include antivirus or antispyware programs, so you definitely need some sort of add-on security software. If you don’t want to pay for it, there are free alternatives available.

How do we determine when to purchase a new PC? Our current Dell is about five years old. I’m feeling a little worried because I have my music and photos on the computer and don’t want to lose them.

There’s no universal answer to your question. In general, I don’t believe people should replace computers that are working well for them just because they reach a certain age. On the other hand, five years is pretty old for a PC. At that age, the odds increase that the hard disk may develop problems, and that newer versions of the software you like will require hardware upgrades that may cost more than you want to invest in an older machine.

Assuming your Dell is working fine, that you aren’t a power user, and that your music and photo activities are simple and basic, there’s probably no urgent need to replace the PC. But, to assuage your concern about “losing” your pictures and music, you might back up those precious files to an external hard disk or an online backup service.

Last week, you compared the start-up time of Windows Vista to Apple’s new Leopard operating system, and found Vista to be much slower. But you used different laptops for each. What would the numbers be on the same Macintosh running the two operating systems?

I ran the tests again on a single computer, a fairly new Apple iMac, which can be started up, and restarted, in either Vista or Leopard. I used the Mac’s Boot Camp feature, in which only one operating system is running at a time, has its own dedicated portion of the hard disk and fully controls the hardware. The machine uses an Intel processor and other key components commonly found on Windows machines, and runs Windows just like a Dell or any standard Windows PC, without any involvement from the Mac operating system.

This Vista installation doesn’t include any of the speed-robbing trial software commonly included by PC makers, though it does have security software from Symantec. However, the test results were very similar — Leopard started and restarted much more quickly than Vista did.

In this simple test, I timed both operating systems from a cold start and a restart until the computer was fully ready for operation, with the hard disk quiet and the network connection established. The cold start, beginning with the computer completely off, took Leopard 46 seconds, but took Vista one minute and 42 seconds. A restart, beginning with the computer running an email program, the Firefox Web browser, and Microsoft Word, took one minute and two seconds for Leopard, and three minutes and 17 seconds for Vista.

You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital Web site, http://walt.allthingsd.com.

Write to Walter S. Mossberg at mossberg@wsj.com

Q. Is there any way to watch high-definition TV on a Mac in real time — not downloaded from a service?

A. As on Windows computers, there are add-on TV tuners for Macs that can both receive and record TV programs in real time. Some of them can handle high-definition programming. The best-known company that sells such tuners for the Mac is called Elgato, at elgato.com.

Q. I’m interested in your perception of the Treo’s future. I currently use (and generally like) a Treo 650. I’d like to upgrade, but I’ve read recently that Palm’s future is uncertain. I wonder if you think the Treo is on a slippery slope down, while the Apple iPhone will likely improve.

A. I do believe that Palm has allowed its software to stagnate and hasn’t moved fast enough to make its hardware thinner and cheaper. However, there are also some positive signs at Palm. Its new Centro phone is pretty good, smaller and less costly than a Treo. And the company is receiving an influx of funds and talent from a group of outside investors with experience at Apple, among other places.

Palm’s fate and future may depend on the success of a project it has undertaken to create an entirely new operating system. But the outcome of that effort won’t be known for quite some time.

The iPhone, which is already very good, will likely get better, as it is just at the beginning of its life. It has raised the bar for other smart-phone makers, such as Palm, especially when it comes to software. But I expect other companies to match at least some of the iPhone’s features and style, which means Apple will have to hustle to keep its lead. In the past five years, Apple has done very well at staying ahead of competitors in the design of its computers and portable music players. But the cellphone business is full of companies with more imagination than the typical PC maker and more resources than many makers of portable music players, so the challenge for Apple will be greater.

Q. My mom is legally blind and has difficulty working with email and downloading files. I try to help her by phone, but it never works, and we live far apart, so I can’t just go over to help her. I would like to install an application on her PC where I can take over remotely from home. Do you have any suggestions for this type of application?

A. There are a number of possibilities. One very simple option is a program called CrossLoop, at crossloop.com. Some versions of Windows, such as Windows XP Professional and Windows Vista Ultimate, also have remote desktop control built in.

You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital Web site, http://walt.allthingsd.com.

Write to Walter S. Mossberg at mossberg@wsj.com