This is a great graphical sim and very easy to install and use.  Connects via USB lead to your PC and can be used on a spec of 400mhz or higher with 64 mb ram, a 16 meg video card is required to run the 3d part of the software.

The sim also has a section to allow you to make alterations to the planes and helicopters by altering wings, rotors, engine sizes, fuel tanks etc.  A number of scene shots and back drops are available including the models.

See the photo section for screen shots of the sim.