I've tried to get an answer to this one but I've had trouble getting concrete information. I have an older voice plan on AT&T. Is it possible to tack on the data plan like you were able to do with the old iPhone, or do you HAVE to pick one of the new voice/data plans? I do not currently have an iphone but I am upgrade eligible. I just don't want to lose my older, slightly better voice plan. Thanks if anyone can help. 