I have an old unlocked Treo 650, GSM (I think it supports 900Mhz and 1.8 Ghz), will it work okay in EU countries? I presume so...

A friend is vacationing in Europe for 11 days and wants to stay connected with the U.S. What is the best way? He wants to be able to send and receive text, pick up voicemail, place and receive calls. What is the best and most cost effective way??

I am thinking about loaning him the 650, but he will need a SIM card with service. Should he get one here in the U.S. before he goes? If so, where? Or, should he get one when he gets there? If so, what carrier/how?

I would appreciate any advice. Cheers.

Edit: His U.S. carrier is Sprint, CDMA, non-international phone.