I wanted to do the go-phone plan as well, but heard a number of people say that using all 9's as a social resulted in AT&T contacting them.
I accidentally stumbled on another method that may be of use. My mailing address is a Rural Route (RR # and Box #). Apparently the system has no idea what this means and will return the credit check inconclusive and offer you the gophone plan as an option. When my credit check failed I got a phone call from AT&T rep within minutes and he explained that rural routes are not recognized, but he could offer me the 2 year plan. I told him I'd prefer the gophone plan on my screen and he asked if i was sure and then reminded me that I can also upgrade to a post-pay contract account at a later date.
For further confirmation, a coworker also lives on a Rural Route and had the same experience, minus the phone call from AT&T.
So if you have a P.O. box address or a Rural Route address you will probably be offered the gophone plan through itunes.
