PanoLab Stitch multiple photos together to make panoramas. A little clunky, but still fun.
Photo Radar This map is more about helping you take good pictures -later- than it is about taking pictures with your phone. The app geotags a phone snapshot, helping you find your way back later when you have your higher rez camera.
GorillaCam This is simply a great replacement for the iPhone's native camera app, and it's free. Touch-anywhere shutter, zoom, time lapse capture, bubble level and more!