MicroSIM card is no different from the normal simcard, only size differs. I saw a few offers for ipad arrangements with The PhoneHouse, though it was all contract based.
Why not use a normal simcard?
Look here:
Make a Micro-SIMCARD from a SIMCARD
WIKI about the Micro-SIMCARD
"The newest incarnation known as the 3FF or micro-SIM has dimensions of 15 mm × 12 mm. It can easily be broken off to be used in a device that uses the smaller SIM."
Cheers!