FMS is an RC flight simulator software package.
It's not as realistic as Real Flight, but it's available for FREE.
There's a guy named Matt who's putting himself through college (or was) by making and selling PC interface cables so you can use your own transmitter with the software. (Otherwise you have to use a joystick or your keyboard.)
This is a link to Matt's site. He used to sell the interface, with FMS on a CD, for $24 shipped. Or around there.
Not sure about the price now, but....
http://www.mattclement.freeservers.com/fms/fms.html
Good Luck!
Dennis-