You can usually find something at an airport, or just walk into a local outlet there. You can research the different carriers and rates online.

zjc2a said:
Anyone know the best Place for an prepaid Sim card for Western Europe, namely Spain and France?

Try this link:
http://www.howardforums.com/showthread.php?s=&thread ... »

Kinda long URL, but you can do a search at Hofo if it doesn't work. Hofo has a sticky thread on International pre-paid - people have posted their experiences with various pre-paid networks all over Europe & elsewhere - Good stuff!