oldcode - 3:32 pm on Jan 25, 2012 (gmt 0)

Hello all. I'm seeing many ecommerce sites use the "small charge verification" concept to validate customer credit cards. Basically, charging a small amount (under $10) to the card prior to allowing the item purchase to go through. But I don't see any standard way this is done. My question is this:
Does anyone know of a tool I can purchase to create this small charge? Something tested and ready to go would be preferable to building it. Any suggestions would be welcome. Thanks much