Hi Hippiechix,

what you need is a so-called tri-band cell phone that works in all three frequency ranges that exist worldwide. For such a tour, I would suggest that you get a rather simple one, without features like camera, MP3 player etc, because that simply uses up the battery very quickly. Depending on where you are, you might not have a chance to recharge the battery. Also keep in mind that mobile phones usually have a very limited memory capacity, i.e. you will need to download pictures/videos/MP3s to a computer quite frequently. Are you planning to take a laptop with you?
Before you get a phone, make sure that your provider has a roaming contract with providers in the countries you wanna visit. The best phone doesn't help you if you don't get a connection.

I use a Siemens S55 and it works perfectly here in the US.

Enjoy your trip!

Take care,

Christof