After posting an order on the ecommerce site I’m working on, we have to get tax information and authorize the users credit card. Both of these functions (Vertex for tax and viaWarp for Credit Cards) live on a different machine than the webservers in the cluster, so I thought it made sense to use SOAP to send and retrieve messages re: Credit Cards & Tax information (especially since the IT department would like to re-use whatever we build with other pieces of their infrastructure). This is a great introduction to using SOAP, ASP and VB.