Somewhere I saw a picture of the new AT&T MicroSim for the iPad.
It was the usual credit card sized holder where you punch out the SIM. The twist was the SIM also had punch outs -- you could punch out a regular size SIM or a Micro SIM. That would seem to say cutting a regular SIM down to size should work.
But I'm a software guy and that sounds too much like hardware, so I'll just buy one
