“A Visual Studio add-in that allows you to graphically design .NET Configuration Sections and automatically generates all the required code and a schema definition (XSD) for them.”
Here is a sample project which will show you how to send and receive JSON data from a WCF service using three of the most popular javascript libraries. You can do it without the libraries but why reinvent the wheel. Also, this is actually a VS2008 Studio Template so just download and drop the file into My Documents\Visual Studio 2008\Templates\ProjectTemplates\Visual C#\ and enjoy.
To use the template, goto File\New Project\Visual C# and look to “My Templates” and you should see WCF JSON.
I’ve been doing a bit of WCF lately and picked up on a few things that will be helpful for me to remember. To speed large transfers switch the messageEncoding on the binding to be MTOM, otherwise your data will get base64 encoded inside the XML.
Another good piece:
http://www.aspfree.com/c/a/Windows-Scripting/WCF-and-Hosting/3/