Payment Gateways

We were exploring the various options for selecting a payment gateway for a new business opportunity. Found this site that has a good explanation of payment gateways and compares the popular payment gateways available in the market.
http://www.bestpaymentgateways.com/
The site has a brief explanation on each payment gateway. The following gateways are explained.

• Amazon Payment Gateway
• Authorize.net
• PayPal PayFlow Pro
• VeriSign
• Google Checkout
• Moneybookers
• VerePay
• WorldPay