Getting WCF 4 Release Candidate Documentation
Although I didn't include it in the release candidate announcement, the online documentation collection for WCF has also been updated. While you can navigate between the different framework versions for the reference documentation, some people seem to be having more trouble finding the conceptual documentation and samples, which are not as tightly linked together. Here are the starting pages for those document collections as well as a direct link to download all of the sample source code.