Is the T-mobile G1 (USA) locked?

[LukiSpuki]

Hi guys,
If I take the G1 bought in USA to europe and swap SIM card, will it work for me? I'm planning a 2 month trip (school exchange program), and it would be nice to know.
Thanks,
luki

 

[Ageless Stranger]

You can ask T-Mobile to unlock it for free if you have had the phone a few months