Small Charge Verfication Software

[oldcode]

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

[rocknbil]

Google for preauth, that's a better way to go. It's pretty standard with goods - you do a preauth for the amount, then it sits in your credit card processor witholding funds, but not actually charging them. When the actual item is shipped, you batch the order and it applies the charge.