You get out what you put in

I'm a frequent contributor to the Microsoft HPC forums (http://social.microsoft.com/Forums/en-US/category/windowshpc). There are diverse and interesting threads to follow, and from a completely selfish perspective I've found getting involved there to be an extremely useful learning experience. It's also not uncommon to have a question answered by a member of the HPC product group, who are obviously amongst the most knowledgeable people available.
Basically, if you're embarking on a journey into Windows HPC you can do worse than hang out there!

Trust the product group

This one speaks for itself. My experience of the Windows HPC Product Group has been consistently excellent.  The official Windows HPC team blog is a goldmine of information, and questions to the Windows HPC forums are often investigated & answered by team members. If you have a question or issue, don't hesitate to ask on the forums.
These guys have always been very willing to help wherever possible, and for that they deserve credit.