Microsoft has released Cumulative Update 6 (CU6) for SQL Server 2008 SP1, which you can request here. This is Build 2757, and it has 33 listed fixes, which mainly seem to be focused on replication, SSRS, and SSAS. They have also released CU9 for SQL Server 2008 RTM, which you can get here.  If you are still on the RTM branch of SQL Server 2008, you need to get over to the SP1 branch, since Microsoft support for SQL Server 2008 RTM ends on April 10, 2010.