It’s official. Google is offering unlocked G1 phones to developers for $399. Free shipping too! It’s meant for developers all around the world who don’t live in T-Mobile’s territory so other SIM cards will work.
You can buy the new phone at the Android Market.
Of course, if you’ve already bought a G1 and want to unlock it, there is a way, although the big warning is that if you mess up on the procedure, it could kill your phone. But if you’re searching around for a way, here is more information.