Yes if you use iphone GPS module finally have GPS functional. This module is in development and will be shipping in February. All software is open source and more applications are being written every day. This module gives you the ability to explore all the benefits that GPS on a platform that is small enough to put on a keychain. Plans are already underway for a stylish plastic enclosure as well.

iPhone GPS module features:
Channels: 16
Update Rate: 1 sample / second
Acquisition Time: Hot: 4 Seconds, Cold: 45 seconds, Indoor: A long time
Serial Output: 1 Serial, 1 USB
Position Accuracy : 2.5m
Protocol Support: NMEA 0183 ver 2.3
Iphone Software: Requires Jail Broken Phone (tested on firmware version 1.1.2).
Software will be open source/community based