OpenAster/SharpChess
SharpChess is a free, open-source computer application that enables you to play chess against the computer. SharpChess is also a chess engine that competes in computer vs. computer chess tournaments. The main goal of this project is to improve SharpChess's chess playing strength. Find out more about chess programming at SharpChess.com or the excellent: http://chessprogramming.wikispaces.com/