How do I go about processing a credit card payment?  We just got set-up to accept credit cards from our customers...I want to be sure we do not miss anything... thank you.

Actually, that is the wrong answer.  That link is for paying vendors by credit card.  She was asking about receiving custoemr payments by credit card.
 
If you will not be receiving very many customer credit card payments, then you can enter them through AR-N or AR-C (depending whether it is before or after invoicing) and use the credit card terminal approval number as the "check number" perhaps with a a letter prefix - A for American Express, V for Visa, etc. and post the payment to your bank account.  However, if you will be processing quite a few of them, you may want to set up a dummy "checking account" in AD-B called "Credit Card Pending" and post the payments to that account.  Then, a few days later when the funds actually make it to your bank, use GL-K to transfer the lump sum amount from Credit Card Pending to the operating account.  You can then use GL-J and reconcile the Credit Card Pending account to verify that all charges did in fact make it to your account and enter any service charges deducted from the amount transferred.