All of us excited iPhone hopefuls have been up, down, and all around these forums and other sites to get the most information possible so we will be ready to make our moves tomorrow when iPhone is ready to buy! Unfortunately, for us 'existing customers', I've been informed that it might not be so easy to upgrade our services with a mere $20. For people like myself that are weaved into shared plans or family-type plans, selecting just a data plan might not be possible. I spoke to an AT&T rep about ten minutes ago and she proclaimed that for my sort of line -- one that shares minutes with other phones -- it would need a new iPhone voice plan. (Meaning it does not currently have its own voice plan -- to begin with -- and would need to pick one of the plans that were announced recently to start.) I was originally skeptical about whether or not you can just add the 'existing customer' plans to your current line as though it were a new feature; adding the data plan/texting capabilities to iPhone. Maybe I'm just not lucking out, or others in this position as well, but in the end Apple hasn't really explained thoroughly what happens for current customers.