David,
If I remember correctly, your customer has to set up a merchant account. They would then give you that information to work with. Secondly, I remember seeing some OCX's advertised somewhere (VBPJ? FoxTalk?). You set some properties and processes the CC information. Oh and there is a MOD10 validation class in the downloads section here in Universal Thread that I have used before.
You should get that right away.
HTH,