I Use a shopping Cart Through Securenetshop. They can actually link to ebay records and pull all the info from a buyers records after a sale and all that buyer has to do is enter the email address associated with ebay and the records will automatically be prefilled for them. All they have to do is enter the Credit card numbers and they are set.
It took me a little while to get it just right. I had so many people asking me how to pay. But once I placed detailed instructions on how to pay in my auctions. I have no more problems. Maybe 2 people a month ask me how to pay.