Normally, 3G will work just fine, but every now and then it seems to be unable to find service and shows "No Service" in the top left on the status bar. When this happens, I can switch 3G off and get service again, but only on Edge. When switched back to 3G, the phone goes back to "No Service". As far as I have been able to tell, only a reboot will regain 3G access again. I have a sneaky suspicion that the problem is my Volkswagen iPod connector. Through the various OS releases on the iPhone, the connection to the stereo has worked in varying degrees, and I think it's because it was not really designed for an iPhone. It asks me every time I plug it in (sometimes twice) if I would like it to go into airplane mode (I always reply 'no'), but I'm suspecting that the code that does that check in the iPhone is not as stable. This is just a suspicion, though... no proof. I'm going to not connect my iPhone to it for the next few days to see if that has any effect on the "No Service" problem. If anyone has any other suggestions as to what could cause it or have experienced this issue, I'd love to hear about it... maybe we can find a set of common circumstances that cause it.