I believe the main thing with GSM phones is what frequency it expects to transmit and receive GSM data on. This varies from country to country depending on what

I believe the main thing with GSM phones is what frequency it expects to transmit and receive GSM data on. This varies from country to country depending on what frequencies the various telcos could purchase at the time, but these phones support "GSM 850/900/1800/1900" and "UMTS 2100/1900/900" which I believe cover the majority of countries.