Update Center for Microsoft Office, Office Servers, and Related Products is a place where you can Find and Manage updates in one place for Office, Forms Server, Groove Server, PerformancePoint Server, Project Portfolio Server, Project Server, Search Server, SharePoint Server, and Windows SharePoint Services. Use the RSS feed on this page and Microsoft Update to automatically receive information about updates and to download the updates themselves.
Here is the list for the recent released update:
2007 Office system
SharePoint Server 2007
Project Server 2007
Search Server 2008
Windows SharePoint Services 3.0
Office 2003
SharePoint Portal Server 2003
Project Server 2003
Windows SharePoint Services 2.0
Office XP
SharePoint Portal Server 2001
Project Server 2002
SharePoint Team Services
For the updated list visit @ Update Center for Microsoft Office, Office Servers, and Related Products
Hope this helps!!!