I want to get the new iPhone 4S, there are 2 phones on the account, my wife's gets the $199 offer, my account does not, If I order the new iPhone 4S on my wife's, can I just swap sim cards so I get the new phone?
It's easier than that. Just order through AT&T on her line. When the phone arrives call AT&T, tell them you're doing an "upgrade swap". They'll take care of it and you don't even swap sims. Just leave the new sim in the phone. Takes about ten minutes.