The WCF 4 sample collection is now available as a direct download independent from the framework or SDK release. The collection includes over 200 WCF samples from both .Net 4 and past releases. These samples go along with online sample guides available from MSDN.
Windows Communication Foundation (WCF) and Windows Workflow Foundation (WF) Samples for .NET Framework 4
You can also get the Visual Studio 2010 and .Net 4 training kit which covers a lot more than just WCF. Training kits are a collection of presentations, hands on labs, and demos related to the new features in a release. The kit spans a variety of technologies from the Visual Studio tools, languages, libraries, and Windows 7.
Both of these are meant to be used with .Net 4 and Visual Studio 2010 but most of the content doesn’t require the dependencies to be useful.