There is a new version of Microsoft Flight Simulator, due to be released on February 29.
http://www.microsoft.com/games/flight/#
Apparently you can try it out in demo mode, in advance of that.
Also, for those of you who own an iPad there is a really cool free app called Breitling Reno Air Race. I think it's fun, and challenging.
http://www.breitling.com/en/the-game-2011/
The movie is interesting
http://www.breitlingthegame.com/en/the-game-2011/film/