I've been trying out Apple's new 3G iPhone for the past week. Overall it's a significant improvement over the current model, and with its lower price of entry, it will bring millions of new customers to AT&T, the sole U.S. carrier for the product.

The most significant changes are faster 3G data speeds and built-in GPS, features that have already appeared on other phones, but have a bigger impact on the iPhone. Web sites open much more quickly and downloading e-mail with attachments is faster. Browsing, one of the best features of the iPhone, went from being agonizingly slow to reasonably fast. Sites such as the New York Times, Wall Street Journal, Google and Yahoo opened in 15 to 45 seconds, as compared to 45 seconds to almost two minutes on a non-3G iPhone.

I found that 3G on AT&T's network doesn't yet have as broad a coverage as Sprint and Verizon. There were numerous times when 3G reverted to the slower 2G Edge speed, even along major highways such as I-5.

The GPS is integrated with Google Maps and can pinpoint your location precisely. There's no built-in application that supplies turn-by-turn directions, but that will likely become available from third party developers. The GPS is used with a number of the add-in programs to provide local information, such as where to eat or shop and which of your friends are nearby. It's even used when you want to check what's playing at the local movie theaters. Unlike some of the standalone GPS units, your location is pinpointed in just a few seconds.

The other big improvement is an upgraded operating system that's also available for owners of the current iPhone (free) and the iPod Touch ($10). It adds an on-line store for buying applications, new enterprise features and improvements for managing your inbox, searching contacts and more.

The 3G model looks similar to the original, but is slightly thicker in the middle and has a plastic back (choice of black or white) instead of aluminum to allow the additional radios to work (10 in all).

The phone is supplied with a tiny 1-inch cube charger with non-folding prongs, a USB cable and earphones. The 3G iPhone costs $199 with 8GB of memory and $299 with 16GB. If you plan to store a few thousand photos and video recordings or hundreds of CD albums, the 16GB model is recommended. A two-year contact ranges from $70 to $130 per month for voice and unlimited data. Compared to the original model, that's $10-$15 more per month.

The only downside to the new model is the shorter battery life caused by the 3G power requirements. In my testing I found the battery to last about two-thirds as long as the original iPhone's. The 20 percent low-battery warning occurred about four hours into the day with the 3G model, compared to seven hours on the original, with moderate use of the phone, Web browsing, and e-mail. With all of the new applications becoming available, some quite addictive, it's likely the battery will run down even quicker.

Because the battery is sealed, you may want to carry a recharger with you. (For the car I recommend the small $20 InCharge Auto from ExtremeMac, a small USB charger that plugs into the cigarette lighter.) Also, Kensington makes an external battery for the iPhone -- model 33442 -- that can give it a boost.

One of the best new features available to all iPhone users is the App Store, which opened its virtual doors with nearly 1000 applications, with more being added each day. Some are free and others range from 99 cents to about $30. They can be bought from the iTunes store on your computer or from the iPhone directly.

Here are a few random examples that I tried: Apple Remote (free) turns the iPhone into a remote control for iTunes on your computer and Apple TV; Emerald Chronometer ($4.99), a variety of realistic looking wristwatches that display time, date, sunrise and sunset times as well as numerous other functions; AOL Radio (free) lets you play 150 CBS radio stations from around the country; Las Vegas Blackjack ($2.99), a standard video blackjack game; Bank of America Mobile Banking (free); and Showtime (free) that displays movie times from nearby theaters using the GPS to identify your location. FileMagnet ($4.99, Mac only) transfers documents from your computer to the iPhone using your WiFi connection. It works with a wide range of files including Office, PDFs, images, movies, etc. TruPhone (free) turns your iPhone into a VOIP phone that lets you make low cost international calls over the Internet using WiFi.

Expect to see thousands more of these applications that make the iPhone much more powerful than any other smartphone. But one caution: After a week of testing as I add more applications, I'm finding that the phone is less stable. Its operation is sluggish at times, and it occasionally freezes and needs to be rebooted. I expect these setbacks to be temporary, but this also may be a sign the product or applications were released without sufficient testing.

Negatives aside, it's is a terrific product, better than any other mobile phone for the combination of entertainment, browsing the Web and e-mailing. But it would be even better with a replaceable battery.

Remember the Apple ads asking what's on your notebook? Well, now our government is doing more than asking. When returning to the United States, many citizens are finding that their notebook computers are no longer private and personal. Immigration officials have been searching the hard drives, some using sophisticated devices that copy everything on your hard drive onto their computers in just minutes. "These ongoing baseless searches of electronic devices at America's borders are not 'routine,' they're unreasonable," said Lee Tien, a lawyer with the Electronic Frontier Foundation. "It's hard to imagine something more invasive than a wholesale copying of private files from a personal computer. We need Congress and the courts to recognize a standard for digital searches and seizures at the border that protects the privacy, property and free speech rights of Americans in the Information Age." The Electronic Frontier Foundation is asking that searches be allowed only with reasonable cause.