Freeware

Arasan
Program for Windows and Linux allowing free distribution.
http://www.arasanchess.org/

BabyChess
Edit and play games on Unix or Windows, supports PGN, and FEN format. Includes a chess engine and client for ICS. [Open Source, GPL]
http://user.cs.tu-berlin.de/~kunegis/babychess/

Dalek Chess
Includes news, downloads, and FAQ for an open source, animated Linux chess game using Doctor Who characters.
http://dalekchess.sourceforge.net/

Egg Chess
Linux or Windows version involving eggs. [Open Source]
http://www.etek.chalmers.se/~e8cal1/sge/apps.html

E.T. Chess
Includes download and screenshot.
http://pagesperso-orange.fr/eric.triki/

Hotbabe Chess
Freeware chess playing program with chatting and joking ability.
http://www.stauffercom.com/hotbabe

Maniac
Windows chess program that plays multiple variants of chess. Users may play with the computer or with other users on the Internet.
http://maniac10001.tripod.com/

NagaSkaki
Windows version by Neels Groenewald with a computer opponent.
http://geocities.com/nagaskaki/

RDCHESS
Chess with a Windows GUI and most of the features of commercial programs.
http://groups.msn.com/RudolfPosch/freewareprogramrdchess.msnw?pgmarket=en-us

YICS
Multiplayer software for using WinBoard, Xboard and other FICS interfaces to play on Yahoo! Chess.
http://www.yics.org/