I have found myself digging through my blog archives several times in the past couple of weeks to send out links to the various posts that I have written about customizing the Windows Media Center Start menu in Windows Vista. As a result, I decided to create an article that contains all of the links to make it easier to send out via email. You can check out the article at this location:
I will keep that article up-to-date with new topics as they are published.
Also, Charlie Owen recently created a really nice sample that demonstrates how to accomplish many of the techniques that I previously described, and I find that it is much easier to learn these concepts with examples that you can register on your Windows Media Center system and observe the effects that they have. This sample will be included in the final release of the Windows Media Center SDK for Windows Vista, so I encourage you to refer to the SDK documentation and samples in addition to these blog posts.