Running Unreal Tournament Servers, by Jack Porter, Epic Games, Inc.
http://unreal.epicgames.com/utServers.htm

• Introduction
• Configuring and Launching a Dedicated Server from Inside the Game
• Launching a Dedicated Server from the Command Line
• Remote Administration
• Performance
• Links

The Admin Page - an Unreal Tournament community run site especially for server administators.

Server Admin Help at UTWorld - another community-run server admin site.