I'm new to this list, so I'm not sure what has been kicked around in this thread.
I just like to bring up that you need to mention on your page that you can store their credit card for future convenience and if the user agrees with that. You also should consider what to do when a credit card has expired. I had one company add 3 years to my expired card and process a renewal payment. That is not legal because it is not the information I have provided... American Express had fun with those turkeys. FWIW, Gerry