If you had previously used the SP2 Blocker Toolkit to block the deployment of Service Pack 2 for Windows Small Business Server 2003(KB940276), on Tuesday, August 12th 2008 Automatic Updates will ignore the registry key and begin offering Service Pack 2 for Windows Small Business Server 2003 to all SBS servers configured to receive updates automatically both thru’ Windows Update and Microsoft Update.

Note: The 940276 SP 2 package is only offered to SBS 2003 servers with no Windows 2003 Service Pack installed to avoid the symptoms described in KB 940276.

More info: FAQ on TechNet