Telephone
Most US and european cell phones work in the D.R. There is GSM coverage for most of the island. Codetel / Claro also has the old PCS system with out a simcard and it works almost everywhere. It will however be phased out for GSM with in the next few years.
If you wish to telephone home you can call from either your hotel or from your nearest Telecommunications center such as Codetel or Tricom. It will be more expensive to phone from your hotel. To call an Europe number, first dial 011 + country code and then the area code + number. To the US and Canada dial 1 and then the area code.