altoGames
Three desktop wallpapers available for download in three different sizes.

Apolyton CS - Call to Power
News coverage, strategy and modification guidelines, game feature information, large archive of CtP related files and bulletin boards.

Civ Land
Collection of maps and other files.

John Bytheway's Stuff
Mars scenario and several guidelines about scenario designing.

Keygen's Call to Power Site
Repository for a PBEM modification file.

Loki - Call to Power
Official website of the Linux port. Offers an overview, screenshots, tips and downloadable demo, extra map and updates for the game.

Martin's Civ:CTP page
Small collection of downloadable modification pack files.

Paul's website
Repository for two downloadable utilities.

Sniper's CtP Site
Lists about the different game concepts and a good screenshot collection.