Quite an interesting article here: http://beta.news.com.com/Microsoft,+JBoss+link+server+software/2100-7344_3-5...

It goes further than I would have expected from Microsoft as it includes working together on Active Directory integration and allowing SQL Server to be a back end.

Only question I have is how much will actually be open-source as the article says "most" JBoss software is LPGL.