Perhaps the biggest rant about the way cool iPhone is the lack of integrated GPS. A solution... One developer seems to be almost ready to roll out GPS for iPhone users - enter locoGPS for iPhone and iPod touch. Developed using open source software, the application is reported to be set for rol-out in Feb. LocoGPS reports to provide 5-10m GPS positional accuracy and will be connected for charging via USB and it appears the keychain size device will connect directly with the iPhone for GPS use. More details over at partfoundry.
The device will sell for about $89. See also monsterandfriends for more on iPhone app development - they are also looking for developers for iPhone GPS projects.