This guide is intended to teach you the basics of the UE3 editor. The “Basic Editor Usage” section is meant to be read in order, from front to back, assuming you’re learning from scratch. Later topics are more specialized, and meant to be read as you need them.
I also created a training DVD for the Unreal Development Kit. The DVD goes into a lot more depth than these tutorials, so if you're interested, click here
Epic UT3 forums - Check sub-forums for editor/mapping/modding discussion
BeyondUnreal Mapping Forums - A large mapping community
UnrealPlayground UT3 Forums - Sub-forums for various editor and modding topics
IceCreamYou UnrealEd Links - A large collection of links to UnrealEd topics organized by subject