Caissa's Web
Play against human or computer. Free demo membership - small fee required for full membership.
Dutch Internet Chess Server (DICS)
Online chess including atomic, blitz, suicide, bughouse, and crazyhouse variants, with tournaments and problem competitions.
Free Internet Chess Server (FICS)
A free chess server with players of all levels, with lectures to help you improve your play.
Internet Chess Assistant Club
Chess playing server with lectures, tournanments, and Nalimov tablebases.
Internet Chess Club
Top level competition for serious players. Chess variants are played here as well. There is a small fee for use of the server.
The Friendly Chessboard
Challenge new or existing friends. Not real-time. Game analysis by Crafty.
Yahoo Chess vs. The Chess Servers
Compares the features of Yahoo chess with those of other chess servers.