Originally Posted by John Clark
Ah. Then, if that's the case, you need a new sim card.
nope, there is a master password for SIM cards called a PUK code, which will unlock it. i'm not sure if the carrier specifically sets it, or if it is something random generated off the SIM ID number.
anyway, moral of the story - call tmobile. it's the same thing if you travel out of the country and want your SIM card unlocked - this is just a sure fire way to get the code without them heckling you for it.