KB968382 - How to obtain the latest service pack for SQL Server 2008
This article describes that Microsoft SQL Server 2008 Service Pack 4 (SP4) is the latest service pack for SQL Server 2008. Additionally, it provides the information for Microsoft SQL Server 2008 Service Pack 3 (SP3), Microsoft SQL Server 2008 Service Pack 2 (SP2), and Microsoft SQL Server 2008 Service Pack 1 (SP1).