- Unreal Development Kit @ the UDN - http://udn.epicgames.com/Three/DevelopmentKitHome.html
- UDK Forums - http://forums.epicgames.com/forumdisplay.php?f=366
- UDN Community Links - http://udn.epicgames.com/Three/UDKCommunityLinks.html
- General level editing - http://utmapping.wikidot.com/unrealed