There are newer versions (August 2006) of the MSF process guidance available for download. There has been a few issues with unzipping the CMMI process guidance. Take a look at Rob's post on this subject. Remember that if you want to replace the guidance on an existing project, you need to checkout the existing guidance from the project portal.
We will be moving the MSFWinBuild site from GotDotNet to CodePlex in the near future. When we move the site, we will also make the process guidance source available on it as we currently do on MSDN. We will update them with major releases simultaneously. However, we are considering smaller releases and community feedback through this forum.