I was writing a proof of concept which uses WCF, WF and ASP.Net 2.0 and across some problems when I tried to call a WCF service from the web application client. Turned out that I spent an hour wasted trying to debug my application because I did not place the proxy.cs file into the App_Code of the web application.
I had it documented down and wrote a simple and straight forward tutorial on how you can use a web application to access and call a WCF Service. The article is uploaded into the article section here
Hopefully this tutorial can be useful for someone.