I know that T-Mobile can become Orange and Verizon is a no-brainer, but what about AT&T? I have a new phone from AT&T and wonder what carrier I'll need to go with.
It depends upon your phone. In the past, AT and T was TDMA which is not used in the DR. If you phone has a sim card, however, it is GSM and can work with either Orange or Claro.