eZ publish comes bundled with a PayPal extension. This extension enables credit card processing. Information on how to install it is found here: http://www.ez.no/ez_publish/documentation/building_an_ez_publish_shop/extending_the_shop_with_a_paypal_payment_service
There is also an extension for Worldpay available in the contributions part of the community.
Additional proprietary payment gateways are also available.
