Several years ago Google entered the payment processing business with their own product called Google Checkout http:checkout.google.com  The rates are very competitive and it's an easy system to work with. Google Checkout is compatible with dozens of third party shopping carts and they also have one of their own, although I can't attest to it's use because I have never used it.

As with all things Google it's a great service.

Payment Acceptance Resources:

Payment Processing:

PayPal:  “The easiest way to accept credit card payments on the Internet, and it’s free to join”

ClickBank: “ The leading source for information based products. A good place to start selling your information based products or your online service 

PayDotCom: “Very good competition for ClickBank. Some of the selling fees are lower than ClickBank. Free for one product listing, sign-up fees for more than one. Hooks into your PayPal account but offers easiest way of setting products up”

XSite ProVer. 2  ”Gets a mention here because the newest version, Version 2, incorporates a very simple way of creating buy buttons for PayPal.”