So people are unlocking their iPhones right and left, but I've been unable to find an answer to the question of wireless data on other carriers. For instance, I have T-Mobile (US/Hawaii). If I were to get an iPhone and unlock it, what plan is needed to prevent a massive cellular bill? I already have unlimited service for my BlackBerry... Would I be able to keep that, or would I switch plans? Do we want to create a recommended plan list for iPhone on other carriers?