Since iPhone 5 is coming, I'd like to ask some questions about unlocked iPhone. I'd like to buy iPhone from official Apple store, because the iPhone in my country is quite expensive (about 200$ more than the unlocked one) and also they don't offer iPhone in white. So, if I buy the unlocked one for 649$ (or whatever the price will be) will I be able to use whichever carrier in whichever country? Just put the SIM from the old one to the new? Thanks for answers.