http://www.sqlservercentral.com/blogs/sqldbauk/2010/12/18/sql-server-2005-sp4-released/

SQL Server 2005 SP4 Released

By Gethyn Ellis, 2010/12/18

Steve Jones mentioned recently that SP4 for SQL Server 2005 is on its way because Microsoft closed his connect item.

Well looks like it was released yesterday, you can download it here:

 http://www.microsoft.com/downloads/en/details.aspx?FamilyID=b953e84f-9307-405e-bceb-47bd345baece&displaylang=en