Direct Payment Solutions (DPS) offers the PX Pay method for processing
credit card transactions in realtime via a [DPS] Hosted Payments Page.

PX Pay allows merchants to send transactions to Payment Express® via HTTPS posts to https://sec.paymentexpress.com/pxpay/pxaccess.aspx. Payment Express® responds with a unique URL for an SSL secure payments page at which the user will be prompted to enter their credit card details and complete the transaction. The result is displayed and the user is automatically directed back to the merchant's website. The result and other transaction details can then be extracted by the merchant. PX Pay is platform independent as transaction requests and responses are made using XML which can be generated and read in any programming language.

Please refer to the link below for more details.
http://www.paymentexpress.com/techni...ted/pxpay.html

More...