Allegro:A free and popular game programming library.
AllegAVI: Library for playing AVI files with the Allegro library. Can play video and uncompressed audio. Only for Mingw32 and MSVC.
Allegro Webring: A collection of related sites.
Allegro.cc: Game developing community network, software directory, and up to date information pertaining to Allegro programming and gaming.
AllegroGL: An add-on library for Allegro which allows applications to use OpenGL for rendering.
AllegTTF: Anti-aliased text output and font loading routines for Allegro.
Allegutl: Utilities related to game development with accent on allegro library.
Gameprog: Tricks, techniques, tutorials, and several open source games to use as examples.
JGMOD: An Allegro add-on library which enables your Allegro programs to play files in the MOD music data format.
Striker: A tile map library written in C for Allegro. Runs under Linux and DOS, possibly Windows. [Open source]
Thunderstrike Games: Several free games made with Allegro and DJGPP. Full source code available for various games.