My very old phone has worked for me all over the UK and as far as Romania and Kurdistan. I bought a local SIM card for it in Turkey because that was a lot cheaper, but I've never had problems like Deckman had. Europe and the Middle East do things more logically and consistently than the US.

This summer I couldn't resist sending a text message while getting a lift on a horse-drawn hay wagon in eastern Transylvania, having seen the locals do it. Nearest main drainage was 50 miles away and hardly any TVs, but mobiles worked fine.