The only time I ever overheated my phone was a very hot/sunny summer day when I returned from a ride, and left my bike/phone sitting in the direct sun, and I forgot to shut off all the stuff I had going on (gps, iPod, etc) or unplug it.
I've never had a temp problem otherwise.
"turn it on man, turn it on-whatever, whoever you are-TURN THE FAWKER ON!" -Herbert Foster Gunnison
00 KTM 640 ADV