I am taking a trip and would rather not lose my new 3G iphone on it, but if I lost my old 2G, I wouldn't mind so much as its scratched up anyways. Would it work if I popped the SIM out of my 3G and put it in my old 2G? I have a legit AT&T contract. I don't want to screw anything up. UPDATE: I did try this but it wants to activate the 3G SIM in the 2G with itunes, and as I'm going on my trip tomorrow for 6 days, I don't want to do anything to screw up my iphone service. I suppose I will just use an old unlocked GSM phone with my iphone 3G sim. I know that works.