So you have your iPhone, and you have this “unlimited” data plan with it, why not use it to it’s fullest? Cre.ations.net posts detailed instructions on how to tether your iPhone to your laptop, allowing you to access the web over your iPhone’s EDGE network. There is also a video showing it in action.
This will be dead slow, but at least it’s some sort of internet access. To complete the task you will need various hacking tools so you can get right into your iPhone that give you the ability to SSH the phone over an ad-hoc network. Be warned, you may get into some trouble from AT&T because “unlimited” doesn’t usually mean unlimited when it comes to cell phone carriers.