Microsoft has recently released various SQL Server related documentations and here I have listed them here for quick reference.
The Microsoft SQL Server protocol documentation provides technical specifications for Microsoft proprietary protocols that are implemented and used in Microsoft SQL Server 2008.
The SQL Server data portability documentation explains various mechanisms by which user-created data in SQL Server can be extracted for use in other software products. These mechanisms include import/export functionality, documented APIs, industry standard formats, or documented data structures/file formats.
The SQL Server standards support documentation provides detailed support information for certain standards that are implemented in Microsoft SQL Server.
Download the scripted system configuration gathering tools. The Microsoft Product Support Reports utility facilitates the gathering of critical system and logging information used in troubleshooting support issues.
Reference: Pinal Dave (http://blog.SQLAuthority.com)