I found a Android Phone?

[Mike]

I found a android phone on the ground this morning. It is the G1 google phone. I have t mobile and i tried putting my sim card in and it wont let me actually use the phone. Like i can turn it on and it has this tutorial menu and i click next and it takes me to a gmail sign in menu. Well i try to put my account in and its wont let me go from there. I dont have internet and i know you dont have to have internet for this phone. I heard there is a way to crack it. Anyone know how to help me???