Unfortunately, there’s not much you can do with the G.P.S. According to Apple, the iPhone’s G.P.S. antenna is much too small to emulate the turn-by-turn navigation of a G.P.S. unit for a vehicle, for example.
Instead, all it can do at this point is track your position as you drive along, representing you as a blue dot sliding along the roads of the map. Even then, the metal of a car or the buildings of Manhattan are often enough to block the iPhone’s view of the sky, leaving it just as confused as you are....
Unfortunately, most of the standard cellphone features that were missing from the first iPhone are still missing. There’s still no voice dialing, video recording, copy-and-paste, memory-card slot, Bluetooth stereo audio or phone-to-phone photo sending (MMS). And when the battery needs replacement after a couple of years, you’ll still have to pay Apple $86 for a replacement
http://www.nytimes.com/2008/07/09/t...?_r=2&pagewanted=1&ref=technology&oref=slogin