GPSRecorder is an app that transforms your iPhone in a fantastic GPS tracking device. It works like this:
You launch the app and start recording. Then you put it back in your pocket and go out running, hiking, riding or taking pictures.
The iPhone application records your position and time. While recording, you can use the map to see your track and use the map, or use the compass to know your direction.
Once home, you can review your track, speed and map, or export it to google earth, trailmapping or everytrail, or add geotags to your pictures with HoudahGeo.
GPSRecorder exports your data in common formats such as gpx (for gps data interchange) or kml (for google maps & google earth). You can use that data in almost any GPS-aware application (HoudahGeo, trailrunner, trailmapping.com, 321run.com)