I got my iPhone 4 on launch day and it's worked great for me so far. However, just today, I got a "No SIM" message 3 times. I haven't touched the SIM door and the phone has been in a iFrogz Luxe Lean case the whole time so there's no apparent movement at all. The only thing that crossed my mind was that today does start my new billing cycle with AT&T. Is there any chance that they have some issue with my phone today since I had upgraded from a 3GS? It's a stretch, but I'm trying to figure this out. Makes no sense that it came up three times, but then after a while went away. Bigtime fail if I need the phone in an emergency or something. Anyone else experience this with their iPhone 4? Thanks!