Hey guys, My girlfriend has a contract with ATT (just for a regular phone). I'll be getting the iPhone 3G S this Friday. I'm assuming that I'm supposed to switch sims with my current iPhone 3G (put the new sim from 3g S into my 3g and vice versa). I'm giving my iPhone 3G to my gf. With the new SIM inside the phone, is it a simple matter of running through the iTunes interface to port her number/sign her up for the new contract? Does the new contract simply write over/supersede the previous one she had been using? Thanks!