I am going to keep my old iphone and not upgrade it to 2.0. I'll keep it unlocked just in case something happens to my 3G phone (when I get it) so that I can pop the sim in and use it. I mean, I paid full price for the thing, I'm on att's plan and still will be for 2 more years. I see nothing wrong with keeping the old one unlocked for this purpose, I more than paid for it... anyone else?