I'm a bit behind the times when it comes to mobiles, it seems. There didn't used to be this many choices for networks. I'm not even really sure what GSM, TDMA, PCS are. I remember that PCS or GPRS (sp?) was common years ago, but now I hear about TDMA and GSM. Anyway, I hear that North America uses different network(s) than most of the world, so does that mean that if I brought a mobile to Europe, I wouldn't be able to use it? I had a Tri-Band Audiovox phone 2 years ago that wasn't too bad, so is Tri-Band something I should be looking for in a phone? Scenario: I'm Canadian and am living in Australia for school. I may do my PhD in Canada, the UK, or Oz. Not sure yet, but I'd like the option of bringing my phone wherever I go. I'm certain that I was using a TDMA phone for the 9 months before I left Canada for Oz. I had a Nokia 3595, I believe (it was free!!), with the bad colour screen, no camera (thank goodness!), and no downloadable ringtones. I'd like to use one phone. Should I just go to mobile providers in each country and find out which network(s) they use, and choose a phone that can definitely hook up to a decent network in each country? And is Sony-Ericsson really that good? I remember 2 years ago, they were utter crap, and Nokia was king. My 3595 had amazing battery life, great volume, and average reception, so Nokia must still be great. And Motorola is good too, as I've read this here at MR. I took a look at a Handspring Treo 600 at their website, and it looked sweet, but extremely pricey. Not sure what network it works on, either.