http://www.microsoft.com/technet/security/tools/mbsahome.mspx

Announcing MBSA 2.0 Beta
MBSA 2.0 is the next version of the Microsoft Baseline Security Analyzer, which utilizes the Windows Update Services infrastructure for security update scanning.  Please help us improve the quality of this release.  We are currently accepting nominations into the MBSA 2.0 beta program.  To nominate yourself for the beta, visit http://beta.microsoft.com, sign in to the system using your Passport ID and a guest ID of "MBSA20" and complete the survey.