I bought an unlocked Android phone (X10 Mini Pro U20a) for use on Claro’s network in the DR. Claro uses 850 for 3G, meaning that you need to purchase a phone that supports HSDPA/UMTS 850 in order to get 3G on your phone. (ATT USA uses 2100 or 850, and T-Mobile USA oddly uses both 1700 up and 2100 down in order to create a 3G connection). I purchased the phone while in the US last month. The phone worked instantly on ATT’s 3G network, but when I returned to the DR I had to enter the APN and reboot the phone in order to get the phone to run on 3G:

Name: Claro

APN: internet.ideasclaro.com.do

Proxy: blank

Port: blank

Username: blank

Password: blank

Server: blank

MMSC: blank

MMS Proxy: blank

MMS Port: blank

MCC: 370

MNC: 02

APN Type: blank