Yes.......and maybe.........
1. The phones will work if you have Cingular service in the US with roaming........you pay roaming charges when you use them.
2. **IF** the phone is unlocked you can just buy an "ORANGE" chip for under $300 RD peso's and your phone will work with local "ORANGE" service.
3. **IF** the phone is currently active with CINGULAR in the US, chances are the phone is LOCKED>......... **IF** you call CINGULAR and ask them to unlock it, chances are they will say NO....... BUT IF YOU SPEAK WITH A SUPERVISOR, and tell them that you live in 2 countries and have had CINGULAR service for over 3 months..........they will guide you through unlocking the phone while you are on the phone and then you just put in the new ORANGE chip that you buy here in the DR.............
.........OR you find a cellular shop in POP to unlock it, but they will charge you for it and chances are it will have to be sent to SANTIAGO and will take a few days and a few pesos......
I have a RAZR, a Samsung (push to talk) and an audiovox PDA all working with both CINGULAR and ORANGE service....