ExaChess 3.1.3: [Shareware] Reads/writes chess game databases in ChessBase, NICBase, PGN, EPD and ExaChess formats. Supports seven "plug-in" chess engines. Updated August 2005

Free Internet Chess Server (FICS): A free chess server with players of all levels, with lectures to help you improve your play

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