AFAIK, the 3GS does indeed have a GPS receiver (I used to have one). In normal uses it combines GPS with info from cell towers and wifi, but in the absence of cell/wifi signals I'm pretty sure it still works off GPS alone. http://gizmodo.com/5015930/giz-expla...iphone-3gs-gps


FWIW: The Android app OSMand allows downloading OS maps to the phone so a data connection is not needed for viewing maps and nav while on the road. Does lots of other stuff too. http://osmand.net/