I discovered an easy fix to crashing iPhone Apps... turn Airplane Mode on and off or shut your iPhone off and on. By doing this, your iPhone re-establishes itself with the cell phone network. This reminds me of troubles I used to have with my old Sprint phone -- the longer I had it on, the more likely I would have problems with dropped calls. According to Sprint at the time, the cell phone needs to periodically re-establish itself with the cell database. This seems to have worked for me with the iPhone, as my crashes were always occurring when the iPhone was interacting over the network, such as trying to establish my location.
Note that I have a first generation iPhone on firware 2.0.1. Let me know if this works for you or not.