BALROG - Genealogy and chronology of roguelikes.
Hajo's library - A collection of articles concerning game development.
Home of the Underdogs - Great listing of older roguelikes.
Open Directory Project's Rogue-like Category - Indexed collection of roguelikes and related resources.
Roguelike Graveyard - The place for abandoned roguelikes.
Roguelike Restoration Project - The Project's goal is to find old roguelike games (eg., Rogue, XRogue, UltraRogue) and patch them to run on current UNIX and DOS/Windows platforms.
roguelikedevelopment.org - Extensive collection of articles on roguelike game development.