FlightGear a Flight Simulator
Founded in 1997, FlightGear is developed by a worldwide group of volunteers, brought together by a shared ambition to create the most realistic flight simulator possible that is free to use, modify and distribute. FlightGear is used all over the world by desktop flight simulator enthusiasts, for University research and education, for a variety of aerospace engineering and visualization work in industry, and even for interactive exhibits in museums.
FlightGear features more than 400 aircraft, a worldwide seamless scenery database, a multi-player environment, detailed sky modelling, a flexible and open aircraft modelling system, varied networking options, multiple display support, a powerful scripting language, and an open architecture. Best of all, being open-source, the simulator is owned by the community and everyone is encouraged to contribute.
Have heard that with the right equipment playing the FlightGear simulator could be used as pilot hours towards a pilots license. The features available in this open source project are amazing, not to mention just the scenerey would fill more then 3 DVDs. Check out the feature list at http://www.flightgear.org/about/features/
Start downloading FlightGear for free on Windows, Mac, & Linux from http://www.flightgear.org
Watch FlightGear in action