For those of you watching over the past couple of weeks, you may have noticed an out-of-band, mid-CU-cycle update to SQL Server 2008 SP1. The fix to a cluster issue was available only for the SP1 branch; RTM users had to employ a kludgy workaround (see the "WORKAROUND" section in KB #976761). There was also an Analysis Services issue uncovered recently, with the only fix available for SQL Server 2005 SP3.
Last night, Microsoft released official cumulative updates for both the RTM and SP1 branches, which deal with both of the above issues, among many others:
SQL Server 2008 Cumulative Update #8
SQL Server 2008 SP1 Cumulative Update #5