Setting up monitors for flight Sim Games

[CDP88]

I'm about to start building a gaming pc, mainly for flying games. I've been looking at other peoples pc's and some people have 3 monitors connected together and they'll show just the sky, and they'll have a fourth monitor and it will show the instrument panel. How do they do that?? I know how to connect 3 monitor, but I don't know how to set the monitor up like that to show the different images.
This guy has his pc set up to do that.

http://www.thebestcasescenario.com/forum/showthread.php?t=28&page=6

[pangea33]

I don't have an answer for your question, but your post made me think of this guy's setup: http://teamshocker.com/pics/Flight_Simulator.JPG