If these rumors are true, & you just can't wait for six months after its introduction, you're going to have to buy your iPhone from Cingular.

"Apple's exclusive contract with Cingular is said to be good for the first six months, sources report, meaning other providers will be able to sell the phone in the second-half of 2007. Cingular had an exclusive on the Motorola ROKR—the first phone to feature iTunes—when it launched last year."