I use
http://propay.com and I've also used
http://2co.com (2CheckOut). They each work a bit differently in what cart systems they will connect to, so depends on what/how you want to use credit card processing as to which would best suit your needs.
For example: ProPay allows you to call in and manually process cards - which is good if you are a craft merchant selling at craft fairs and need to authorize a credit card at an event like that.
2CO does not have the phone-in authorizing feature, but it does connect to more shopping cart systems than ProPay for a more seamless online shopping.
So it depends.
Again, PayPal does it all - even accepts credit card funded payments from customers, even if they don't have a PayPal account.