Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7)
Probably not. I upgraded my wife's 3GS to an IPhone 4 and since she was already in an unlimited plan, she was able to keep it. Unfortunately for me though? I terminated my contract a few months ago so now I'm stuck with a 2GB plan.