here is the site where you can see what the country is using.
make sure you have unlocked 3G, wcdma, quand band gsm phone. like nokia Nseries, nokia6630 and 6680 that work anywhere in the world. just click the country that you going to.
GSM Operators, Coverage Maps and Roaming Information - Countries/Areas

I've been asked by my boss to research the potential for maintaining cell phones in our office for use in international travel. Since most people in our office only travel out of the country once or twice per year, I recommended that we use airport kiosks to rent a phone if needed.

She didn't seem to like that idea, so I suggested that any phone would work as long as it used GSM technology, as a CDMA phone would not function in Europe.

She also disagreed with this and expressed certainty that some sort of "bridge" technology existed, or that a users SIM card from their own U.S. phone could be brought to Europe and be plugged into a GSM phone over there.

Sorry for the long post, but I'd like to confirm:
-CDMA doesn't work in Europe, and doesn't have SIM cards
-GSM is required in Europe
-Only GSM (not CDMA) phones have SIM cards
-some U.S. providers don;t even offer GSM phones (like Sprint)

Any additional suggestions would be appreciated!