Yahoo! Groups: javajousters - A group devoted to challenges among Java algorithms and Jrobots fights. - http://games.groups.yahoo.com/group/javajousters/
Java Robots Home Page - Download, discussion and documentation. - http://www.mobydisk.com/java/jrobots/
IBM's Alphaworks: Robocode - Offers information, and downloads for Windows, Linux, and Mac. - http://www.alphaworks.ibm.com/tech/robocode/