Beginner's Guide to Redcode: A text to guide newcomers from their very first contact with Core War and Redcode to the point where they can write a working warrior, and are able to proceed to the more technical commands.
Core War: Introduction and links.
Core War Beginner's Guide: Tournaments and a beginners' guide to Redcode.
Core War For Dummies: An introduction and tutorial.
Pizza Core War Server: Torunaments, links, and tutorials.