Here in India (which by the way is fastest growing cellphone market in the world with more than 150 million phones) there is no lock-in in GSM segment. CDMA operators do lock-in in the sense that there are only two operators present in this segment and sim cards are not interchangeable, last time I checked. But the greater part of the market i.e. GSM has no lock-in. Buy a sim and use it any phone whihc is based on GSM technology.