You've surely seen the ads: they're running on TV, in print and just about everywhere but the backs of your eyelids. Sprint PCS is pushing its "Wireless Web," a way to get online information via the window on your cell phone. The company is the first with a nationwide Internet-in-your-hand phone service--but it won't be the last. Nextel has announced one, and others will follow.

A number of phones can take advantage of Sprint's new service, but the object of desire at the moment is a $400 unit called the Neopoint 1600. It can act as an external modem for a laptop computer (more on that later), but the real lure here is walk-around Web access.

It is lovely: silvery and sleek as a trout. The main thing that tips you off that this phone is different is the oversized window on the front and the funny little rubbery pointer that lets you move the cursor around the screen.

When it works, it's a marvel. The screen is clear and easy to read, despite its size. Point to the proper cryptic icon, and the phone asks if you want to enter the wireless Internet service. Click the little button that confirms your choice and (most of the time) you connect to a miniaturized Phone.com "microbrowser" vision of the Internet. The browser features some nifty twists that make the most of the tiny space: Bloomberg news headlines, for example, are stacked several to a page, with just the first few words of each headline showing. Place the cursor on the line, however, and the full headline scrolls across, a little like the "zipper" in Times Square. So "IBM Shares Drop" becomes "IBM Shares Drop . . . After Company . . . Warns Earnings Will . . . Fall for Next 2 . . . Quarters."

The browser itself is a text-only beast: You won't be downloading photos of Pamela Anderson on the little black-and-white screen, nor would you want to even if you could. The Neopoint is all about text: the local weather forecast, stock quotes, airline reservations. Words still count for plenty.

But if you want to be a pioneer, you'll have some arrows to show for your trouble. The Neopoint 1600 a great phone, but a clunky Internet device.

Using the Web on it was a trying task. That is, I kept trying, because several times the network that carries Internet information to the phone was down. Once you're connected, relatively few Web sites offer special phone-screen versions. (That will almost certainly change, however, as these phones catch on.) Even with that compression, reading Web data on the tiny screen was like getting a tall glass of iced tea a dropperful at a time. The company claims that 11-line screen is "jumbo," but only in the sense that there's such a thing as "jumbo shrimp."

And simply entering information was a chore: To get around the info-entry problem, the phone features a neat idea that doesn't actually work all that well. It incorporates T9, a new technology that should make pecking letters out on a phone keypad easy and intuitive. Instead of having to punch each button two or even three times to get the letter you need--the usual way that phones let you enter letters--T9 has a database of likely words and tries to intuit your choice. Great! Unfortunately, in browser mode it read "Yahoo" as "wagon" and "washingtonpost" as "washingtonsorv." It did a little better with proper names in the directory, even getting the distinctive spelling of the name of my wife, Jeanne. But her last name, "Mixon," got translated into "Nixon," a typo that has always galled her McGovernik family.

The wireless life does not come cheap. Current Sprint PCS users can add wireless Internet access for $9.95 per month, or try it out on a properly equipped phone for 39 cents a minute. Package deals for phone and Internet use cost from $59.99 a month to $179.99 a month with 200 free minutes of Wireless Web updates included; the plans range from 300 prepaid voice minutes to 1,200.

Okay, that's the bad stuff. But the good stuff . . . it's a well-made phone, with easy-to-use voice commands and loads of other features. The voice commands, increasingly common in high-end phones, work like this: you enter a number and record a voice command to go with it. The next time you want to call home, just press the right button (the volume button, easy to find when the phone is against your ear) and the phone will prompt you to say who you're calling; say the word, and it dials. If you are one of those dialing drivers--and, let's face it, you shouldn't be--this feature at least reduces the time you spend looking at little buttons instead of the road.

The other features are useful and entertaining as well. It's quite a kick to get the top news off of your phone, and if I actually traded stocks I might enjoy using the phone screen to check on my portfolio. The personal organizer is relatively powerful, and stores up to 1,000 contact names and numbers. It can be synchronized with some of the popular organizers out there, including Microsoft Outlook, ACT and Lotus Organizer. You connect the phone to your computer with a cable provided by the company and can download records from those programs--saving hours of frustrating key-poking. If I ever decided to move up from my paper notebook, a gadget like this could offer serious competition to a Palm or other hand-held.

Most important, Neopoint's package deal gives you software that makes it easy to connect the phone to a laptop computer so that users can log on to the Internet on the fly. It's a huge step forward from the "figure-it-out-yourself, buddy" approach to on-the-road access that has prevailed until now, and promises to make mobile Internet connections much handier in the future. The downside? Because of the way the Sprint PCS network functions, the top modem speed is 14.4 kilobytes per second--about a quarter of the speed of today's standard modems. (Some Sprint competitors, such as Bell Atlantic Mobile, offer comparable services, where the phone acts as a connection but not a browser; these offerings suffer from similar limitations.)

That speed (using the term loosely) is adequate for sending and receiving e-mail, but on many of the graphics-rich sites that you can find on the Internet, your PC will run out of battery power before the page can load. Of course, you've saved a lot of time by not having to hunt for a phone jack on your hands and knees, right?