C# – Hosting and Consuming WCF Service from Same Process

Since WAS is part of the IIS architecture, you need to create a virtual directory in an IIS website (for example 'Default Web Site') that points to physical location of the WCF service you are hosting. Then you will have to create an application on that virtual directory, like you would for an ASP.NET website, or an ASMX web service.
You can easily do this by using IIS 7's management console.

You can read the details about how WAS works in IIS7 here.
For a more step-by-step guide to WAS hosting have a look at this article.

If your service implements a metadata endpoint (typically named mex and nested beneath the principal endpoint, implemented using the mexTcpBinding in this case), you can "ping" it using the svcutil command line utility that's provided with Visual Studio. E.g.,

svcutil net.tcp://mycustomWCFService:8123/MyService/mex

If it throws an error, your service is (potentially) down. If it succeeds, you're (likely) in business. As the preceding parentheticals suggest, it's an approximation. It means there's a listener at the address and that it's able to service a metadata request.