I will be in Europe for 2 weeks and want to be able to use my phone while I'm there. I heard you can turn on international roaming on the T-Mobile plan, but the rates are ridiculously expensive. I also heard that you can purchase a pre-paid sim card online or in the country, but does that require my phone to be unlocked and can my American G1 be used on the European network? Will these sim cards allow me access to the data network? What do you think the best/cheapest option is? Can you get these sim cards online? Can I unlock the phone in Europe if I buy the sim card there? I greatly appreciate your help!