First of all, the term 'unlocked' does not apply to handsets using CDMA technology. If you were to go with a GSM/UMTS provider that would be applicable. In the U.S. this means either ATT or T-Mobile service, or one of their associated MVNOs (prepaid providers) using their respective GSM/UMTS networks. CDMA means either Verizon/Sprint/USCC/Cricket, or one of their MVNOs. (=mobile virtual network operator). Which carrier are you currently using? Which carriers provide service where you reside/work? Those are most important, otherwise, you have a very expensive paperweight.