From Web :
In order to foster innovation and interoperability, Microsoft is making available the protocols in Windows Vista (including the .NET framework), Windows Server 2008, Microsoft SQL Server 2008, Microsoft Office 2007, Microsoft Exchange Server 2007, and Microsoft Office SharePoint Server 2007. These protocols are used by any other Microsoft product to communicate with the aforementioned products.
The release of the protocol specifications and patent licenses enable and encourage a vibrant development community. The result will be smarter, interoperable products that can be released in coordination with Microsoft product releases.
want to read more ??
It looks good, MMS, RDesktop,SMB and a lot more ....
microsoft also on "All non core be open source ' policy