Below are some links on computer chess (not in any particular order):
Winboard (Tim Mann's Chess Page)
Crafty (Dr. Bob Hyatt's Program and Nalimov EGTBs)
Arena (GUI)
FICS (Free Internet Chess Server)
Chess War IV (Chess Engine Tournaments)
SDChess (Chess Engine Tournaments)
Aaron Tay's Winboard FAQ
Winboard forum (Discussion Group)
WBEC Ridderkerk homepage (Chess Tournaments, etc.)
RWBC (Chess Tournaments and live games)
Tom Kerrigan's Simple Chess Program (TSCP)