PrePaid Micro-Sim?

iPad3G

Having an IPad 3G I wanted to take advantage of it while in the states next week. I have been looking online at T-Mobile & AT&T but I can’t seem to find any Pre-Paid Micro-Sim data plan. It’s always these contract plans, so I wondering what I would have to do to get a Pre-Paid Micro Sim for the iPad while I’m there for a few weeks.

I found this site called: iphonetrip but the pricing is ridiculous.

Anyone have any luck with this?