+2  A: 

This won't answer your exact question, but take a look at this post by Scott Hanselman. Basically, the problem is that VS does not officially support parallel builds for managed languages, so you'll have to "hack" a bit in order to get parallel builds.

Anton Gogolev
Thank you. It worked! Hopefully the guys from MS will not only preach paralellism but do something with it in their own tools in the future.
schoetbi