I upgrade iPhone's every "major" release so this will be my third time doing so (iPhone, iPhone 3g, iPhone 4) but two years was a long time ago so my memory is a little bad. However, if I remember right once you switch over to the new phone, your previous phone essentially just loses phone functionality. But can still function like a glorified iPod touch right? So wifi and all the features would work, minus anything that requires a phone plan? Just trying to figure out what I will be able to still use this thing for.