Alex Nicolaou's Space War - Contains Java based version of game, with instructions. - http://www.cgl.uwaterloo.ca/~anicolao/sw/Spacewar/spacewar.html
Spacewar - Contains history, articles covering early development, Intergalactic Spacewar Olympics, code, influences, and game controllers, and Macintosh version of game. - http://www.wheels.org/spacewar/
SpaceWars - Peter Hirschberg and Josh Cogliati's C++ based version of game. Includes features, download of source, requirements, and screen shots. - http://www.digisys.net/users/cogs/spacewar.htm