Official News from Microsoft’s Information Platform
As we've previously written about on this blog, we will be releasing Service Pack 3 for SQL Server 2005 in CY2008 following the release to manufacturing of SQL Server 2008. We've gotten some questions about the differences between Service Packs, Cumulative Updates and Hotfixes. The following blog entry from the SQL Server Release Services team does a good job explaining the new Incremental Servicing Model. Hope this helps.