I think this is one of the best resources that I've seen for building a 3d game in C#. It's much more direct and to the point than any of the books I've seen on the subject.
When will part 6 come out? it looks as though the earlier parts came out about once a month, but it's been 2 months since part 5 came out. Derek, if your reading this, please post part 6 soon!