Multiplayer
Apolyton CS Forums - Civ3-Multiplaying, Civilization Fanatics' Forums - Civ3 - Multip
Apolyton CS Forums - Civ3-Play the World
Discussion forum Civ III PtW related chatter.
Civilization III Fanatics' Center - PtW Expan
List of all the new units in Civ III PtW.
Civilization III: Play the World
Official Civ III PtW website. Offers information about e.g. the new civs, screenshots and desktop wallpapers.