Se ha liberado el service pack 4 de SQL Server 2005.

Como siempre en estos casos es recomendable hacer los test en un ambiente de testing para luego pasarlo a producción

Aquí les dejo los links

SP4 SQL2005

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

SQL 2005 Express SP4

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=26435597-b28e-4568-9d16-017bdf47abdc

Management Studio Express SP4

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=76ea83da-4797-4f11-a834-456ee9dc3764

Feature Pack SQL 2005 SP4

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=7768393b-71fa-4281-83eb-cab08be4fb76

SQL Server 2005 SP4 Data Mining Add-ins  for Office

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=527f476e-2630-4529-881a-f4b7cdd70edd

SQL Server 2005 SP4 Reporting Services Add-in for Sharepoint

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=773dffa6-6cd7-4894-b920-2726869f8700