I have Verizon and an iPhone, and got good coverage in the June Lake Loop a month back. Solid 3G. The coverage dropped significantly as we traveled north of June on the 395 to Lee Vining. ZERO signal in the parking lot at the Lee Vining power station - so much so I didn't even bother taking it with me up the canyon. Bob's right on with the lack of coverage in canyons.
Just a thought, it would be real cool if someone had the exact locations of the cell towers in the Owens' Valley/Eastern Sierra mapped out with maybe even GPS coordinates. That way we could use Google Earth or similar to come up with theoretical line of sight coverage and we could do some real life "testing" in order to have a map of accurate coverage (better than the overly generalized ink-blob map of the entire state that the carriers provide). I know the "will I have cell phone reception" has been asked so many times on both boards that a sticky with this type of map would be very helpful and appreciated.
