Does anyone know the best process for swapping two original iPhone devices? I don't want to upgrade yet given the problems with the iPhone 4 and waiting on the white one honestly. My battery doesn't last very long but I have a spare original iPhone. Is it true that I can't just swap the SIM's? I have to call AT&T and have them update my IMEI to activate the phone that I am swapping to? I get worried there as I don't want to lose my upgrade eligibility or have them screw up my data plan so when I do upgrade I will have that one time option to keep my unlimited plan. Would appreciate any advice on the best way to do this simple thing.