That's good to know. I have an old Orange DR phone, and I was looking in to seeing if the SIM would be compatible with my US Cingular phone. Hopefully when I get back down there, it works.
Most phones brought at dealers (that are brought in by dealers) are unlocked. Most phones brought in by Orange DR are locked. If the phone you buy is offered by the dealer, but not by Orange head office, it most likely is unlocked.
This is easy to find out. Just go to any cellphone repair shop (not the Orange dealer) and ask them to put any foreign SIM into your phone. If the phone turns on and reads on the screen "no service available", "no signal" or similar (basically tring to search for network, without finding it), your phone is unlocked and ready to use with any other SIM card.
If you get "insert SIM", "incorrect SIM", or any other similar "SIM" message right after turning on the phone, your phone is provider-locked. You can usually get the phone unlocked for RD$200 to 300 for most models. Beware, new Motorola phones L7, V3, etc., use something like test-point method for unlocking, it is not that easy, and can damage the software if done improperly, so check that the person unlocking these types of phones is knowledgeable.
For Nokia phone, you can buy unlock codes with entering your IMEI number on the Internet for 5-10 dollars. Just search google for "unlock Nokia phones".
One thing for all travellers - make sure your "my-caller ID" option on the phone is set to "automatic" or "network supported". I spent two weeks in Europe with my L7 with a local prepaid card (T-Mobile SK) trying to find a repair shop (after having it unlocked in DR) thinking something was worng with the phone or it was unlocked incorrectly because I could make no outbound calls and received "call error" message. The same SIM worked in other motorola phone. After some time and googling, I found out to put "my-caller ID") on "automatic" ....... and whoooa it worked (I had it previously set to "always hide my-caller ID")