[PhotoJim]

It's possible, but most GoPhones are not going to support the bands used in Europe. GoPhone service doesn't support roaming, so there is no need for GoPhones to support the frequencies.

If you get the phone unlocked, you can use it with carriers that use those frequencies (I got my GoPhone unlocked and I use it on Rogers in Canada, which does use those frequencies, and I put my T-Mobile and Red Pocket SIMs in it for US use sometimes). That would allow it to work in Mexico, and in some Caribbean areas, but not all (some use European frequencies), and not in Europe.

If you don't care about fancy features, you can get a cheap unlocked quad-band phone like the Motorola RAZR V3, and use it almost anywhere on Earth that has GSM service, including with GoPhone.

You refill the mobile account, not the SIM. The SIM is the piece of hardware that lets your account work in a given phone. Think of it like your cablemodem or DSL modem. It's just a tool to use the service.