I am developing a Windows service that exposes a WCF service intended to be consumed by a Silverlight application, as explained in this blog post: http://mtaulty.com/Communi
I use Visual Web Developer and facing the same issue. My project is already configured targetting .Net 4.0 Framework. The solution for my case is adding reference to my my project by :
right click on References, choose Add Reference and find System.ServiceModel.Web under .Net Tab