We have just implemented a credit card processing web service that allows us to process transactions using the Delphi POS system and the Classic ASP website. In addition, we hope to get it working with the Java-based IVR system.
The web service was written in ASP.NET (C #) and uses SSL encryption, XML validation, XSD, and a load-balanced web farm.
Recently, we have also introduced various services that do everything from checking addresses to creating orders in our ERP system.
source share