The GPS functions in the iPhone 3G are nice, but there is one application I'd really like to see. I have a really old Garmin eTrex GPS. This thing has no built in maps, but it can tell me where I am (lat/lon), what direction I'm going, and how fast I'm going. It will also calculate basic functions such as sun up and sun down times based on position and date. Finally, it can create a track map I can use to either get back to a point of interest I've marked or show a basic line of where I've been. Again, all this is done without any sort of overlay map. I'd love to have a function like this for the iPhone! Last weekend I was out on a short hike. In the area I was in there was no cell coverage. Although the phone would throw a nice blue dot on the the screen, since the maps couldn't download the dot was of no use. The interface doesn't even have a way to see what my current lat and lon are! I'd have really liked to have been able to mark a few points duirng hte hike and see how far I traveled during that walk. Has anyone heard of work being done on an app such as this?