I'll be switching to AT&T/Cingular pretty soon and I had never seen any threads on what service plan you would actually have to sign up for to use the iPhone. I'll be adding whatever phone I get to my brother's existing plan and sharing his minutes/SMS. I was wondering if I could just buy an iPhone (ebay, online store, wherever...) and use it with his service if all that I wanted to do is use SMS, regular minutes, ONLY wifi for net connectivity, no visual voicemail. Is that an option? Will they let you do that?