IPad Question: If I buy a US iPad with 3G functionality, can I use it in Europe?

I don’t need to sign up for monthly service, but I’d like the 3G functionality. I primarily live in Europe, but as an American I travel back and forth frequently and would like to make this purchase in the US.

Does anyone have any experience with this? Can I use a US-based iPad with a European-based (i.e. Vodafone) 3G network? Or should I just go for wifi-only and be happy with what I have?