The Cumulative update package 11 for SQL Server 2008 Service Pack 1 (Build 10.00.2804.00) is available:

http://support.microsoft.com/kb/2413738/

And here you can get the whole information of builds that were released after SQL Server 2008 Service Pack 1 was released:

http://support.microsoft.com/kb/970365/

 And if you are  a little  bit  confused about this CU 11 which isn't a fix of #CU package 1 for SQL Server 2008 Service Pack 2  -  you know what I mean - then read the comment of  Aaron Bertrand :-)

I wish you all a nice "supported" day,

CU
tosc