Im having the same problem. My g2 randomly started rebooting every 2 minutes. It breaks my spirit because I got this phone new little more than 30 days ago from Verizon. Contacted LG today to arange for warranty repair.
I Have a HTC GPE and the same thing has happened to me. I noticed when I got a call and had to use speaker now. I was looking around for a answer and I think we need a new sim.