Yesterday, Microsoft released cumulative updates for SQL Server 2008 RTM and SQL Server 2008 SP1.
Cumulative update package 4 for SQL Server 2008 Service Pack 1
http://support.microsoft.com/kb/973602
Build #: 10.00.2734Cumulative Update 7 package for SQL Server 2008
http://support.microsoft.com/kb/973601
Build #: 10.00.1818
The SQL Server Release Services Blog has not yet posted anything about these updates (which they typically do). On a similar note, I have not yet gone through the list of fixes to figure out which updates made it into which branch (since this is almost never the same).