I created a forum for all game modders called ModParadise. It has sections for discussions, show & tells, and user - made creations. Here are some of the game series that have forums: Rollercaoster Tycoon, Wildlife Park, Civilization, Railroad tycoon, The Sims, SimCity, Simcity Societies, and Zoo Empire.
Link: http://modparadise.forumotion.com/
Link: http://modparadise.forumotion.com/
