I stumbled upon an excellent utility for WCF Testing that comes with Visual Studio 2008 - WCFTestClient.
The tool is an simple way to test WCF clients HTTP and TCP bindings. Some things are not supported, however, for basic WCF Testing, this definitely beats the old ASMX test page.
Note: Also check out the WCFSvcHost utility from Visual Studio to host an arbitrary WCF Service.
Cross Posted from http://blog.tfanshteyn.com/2008/01/wcftestclient-testing-utility-from.html