a little info about fraud prevention

i`m asking this for someone,
so here is the info i can tell u.
lets say i have a adult webcam videosite. members come and use their credit cards to signpu or pay for credits.

what are the tools needed for such a website to verify the credit cards and/or data submited by the members, from what i`ve heard the bigger sites got people who do this stuff, but are there some tools wich are used to validate cards and data ?

Many merchant accounts provide some services for fraud protection. Most make the AVS rules configurable so you can set your own comfort. This at least validates that the card is being submitted with legit info, but doesn't provide full fraud protection.

If you get a provider that supports 3D secure that will cut fraud significantly (provided that you serve US/UK).