GOT MY PHONE!!! :) Doesn't work... :(

[lists at kitepilot.com]

My new phone doesn't see my AT&T SIM card...
The card is OLD.
As in 5 years OLD (or more).
So old, that it broke the Treo when I pulled it out... (screw the Treo) 

I've done some reading about the SIM stuff.
I'm dizzy already, I don't understand none of that stuff... 

Can anybody give a quick and dirty answer about what to do next?
Thanks!
ET