Android's first killer app: Compass Mode

NEW YORK - With a built-in keyboard and Google's open-source Android platform, there may be many things the new T-Mobile G1 can do that Apple's iPhone can't. But at its long-awaited unveiling in New York City Tuesday, one feature stood out: Google Street View in Compass Mode.

Until now, you needed a computer to see the 360-degree panoramic street-level photographs of thousands of locations in the United States, France, Italy, Australia and Japan that Google began making available in May 2007. Google had previously demonstrated Street View on prototype phones running its Android operating system, but the G1 is the first commercial cellphone that has it built in.

Compass Mode on the new G1 takes Street View one step further. Rather than having to drag or click to navigate the images of a particular street corner, you just swing the phone up, down, left or right. The image on the screen shifts as the phone does, creating an effect not unlike the one you would get through the built-in camera if you were actually standing on that street corner, rather than just visiting it in cyberspace.

It's very cool. And there's no reason that Google (GOOG) couldn't make it available on the Apple (AAPL) iPhone or the iPod touch.

But for now, if you want Compass Mode, you have to buy an Android phone.

T-Mobile's G1 comes with a 1 GB memory card and and a removable battery. It will go on sale Oct. 22 for $179 with a 2-year contract. Unlimited Web browsing costs $25. For $35 you also get unlimited messaging.

You can see an early demo of Compass Mode here. For more on the G1s features, see Scott Moritz's hands-on review here.