4 links
ICC Interfaces
chessclub.com
A thorough collection of Java, Windows, Macintosh and UNIX clients which will work correctly with the ICC chess server.
JavaBoard for FICS
freechess.org
A Java Applet allowing to play on the Free Internet Chess Server. Not very featureful, but gets the job done if you can't install an interface. Freeware, Platform independent.
Knights Chess Interface
knights.sourceforge.net
Knights is a relatively new graphical chess interface for KDE. It is, however, already quite featureful and very nice looking. Doubles as a chess engine front end. GPL, Unix (KDE) …