Has anybody tired one from here? I used one for 6 years I lived in Europe and it was cheap and easy. Belize is a little expensive, 0.29 cents USD a minute but that is better than the rates I have been paying.
http://www.aitelephone.com/international-callback.html

I have been trying to get on Skype as well, but have had no luck placing PC to PC calls. I understand this is an ever changing issue, anyone have Skype and is using it?

Skype won't work on BTL.
Callback services are illegal as far as BTL is concerned, so if you choose to use one, keep a low profile about it.

We just got back from AC yesterday. We stayed at The Palms, and successfully used Skype to communicate back to the states. Skype to Skype always worked perfectly. Skype to land line or cell phone worked OK; we sometimes had to make multiple attempts to get through, but we always got through. Hope this helps!