I just bought an iPhone 3GS from walmart on june 5th so I could get the unlimited data plan. I would like to return the 3GS for the iPhone 4 but I have not found any good sources saying that walmart will carry the iphone 4 on launch day. At&t isnt very helpful either as they say I have to return the phone, cancel my plan and loose my number, and go to the at&t store and create a new account if walmart doesnt sell the iphone 4. Does anyone know of any options I have to get the iPhone 4 and keep my current number?