I just got an Apple iphone 3g for my birthday about 2 weeks ago..long story short i just got a new job and since i now have some extra money i want to upgrade to a 3gS since it has not been 30 days yet..my question is since the apple store is the only place that seems to have them in stock can i go to the apple store return it there and get a 3gs in exchange or do i have to go to an att store where i orginally got it return it then go to the apple store ??