Do a search - other than 'who's your sankie?" this is #2 on the hit list of common questions. Most people figure out if you need a phone for more than a few calls which are cheaper to do from a phone office, you can buy a new phone for so little you just do that and use it with cards. Then take it home or give it as a present to someone- you are loking as little as $30.
There is CDMA with Verizon and GSM with Orange. If you are thinking of a get rich quick scheme with bringing in old US phones to resell don't get your hopes up in a world of new $30 phones.