They call it their new, massively scalable data warehousing solution; they say it can load 1TB per hour and support data warehouses in the petabyte range, all on commodity hardware.  Bold claims, for sure, and I bet you're thinking, "I'll believe it when I see it."

If you can get on Microsoft's TAP list (TAP = Technical Adoption Program) and meet other undisclosed criteria, you can see it now.  Otherwise, you'll have to wait until 2010H1.  For more details, see:

http://blogs.technet.com/dataplatforminsider/archive/2009/08/24/microsoft-ships-the-first-technology-preview-for-project-code-named-madison.aspx

http://www.microsoft.com/sqlserver/2008/en/us/madison.aspx