If the latest find from the iPhone OS 2.0 firmware is any indication, then Apple could be readying the iPhone for true GPS support in the near term. It's not clear whether the GPS support will come in the form of integrated GPS hardware or support for dock-connected GPS peripherals, but it does seem likely that GPS is coming to the iPhone.
In addition to the previously discovered location logging feature in the unreleased iPhone OS, Steffen Voigt found references to NMEA positional data within the "locationd" component of the newest iPhone developer OS. NMEA is a data format that is used by positioning devices to communicate positional data - like a GPS receiver communicating the current position to a mobile phone.
There are also references to strings mentioning satellite status, GPS time, type, position, accuracy, latitude, speed, magnetic variation, etc., which is a good sign for iPhone users looking for GPS integration.
Apple's announcement that the iPhone's dock connector will be off limits to third-party developers had iPhone GPS add-on manufacturers scrambling to come up with a wireless GPS solution for the iPhone. With this new find, it seems that GPS hardware could be allowed to play through the iPhone's dock connector. Will Apple roll out support for GPS add-on hardware with the major iPhone Mac OS refresh that's slated for later this year? Or will Apple actually build a GPS receiver into the 3G iPhone? In either case, GPS on the iPhone is most likely on the horizon.