Originally Posted by achoo

How accurate do you want it to be? I have a co-worker who rides and uses his iPhone. He also lives near an airport, and the GPS tracks that come out of his iPhone often look like he was on an approach to land - big looping curves that cut across terrain, houses, shopping centers, and only seem to have a loose correlation with where he actually says he rode.

Nevermind how on longer rides the iPhone battery just doesn't last long enough.