Windows Server Update Services is software which can simplify the task of updating Microsoft products throughout an organization.
There are several prerequisites before installing this, eg.

"For Windows 2000 Server, WSUS requires the following:

•	IIS 5.0
•	BITS 2.0. To obtain this software, see the Download WSUS page.
•	Database software that is fully compatible with SQL Server. Microsoft recommends MSDE 2000 Release A.
•	Microsoft Internet Explorer 6.0 SP1
•	.NET Framework 1.1 Redistributable Package
•	.NET Framework 1.1 SP1. You can also obtain this software from the Windows Update site: Scan for Critical Updates and Service Packs. Install Microsoft .NET Framework 1.1 Service Pack 1 for Windows 2000 Server."

from http://www.microsoft.com/windowsserversystem/updateservices/evaluation/faqs.mspx

This replaces SUS (software update services) which will become inactive in July 2007. A walkthrough of how to plan and deploy SUS is downloadable here, until July 07 anyway.