Simulate an RC Plane ControllerIf you use FMS or other RC flying software that supports it, I suggest using a controller that has two analog joysticks like those found on a PlayStation. These operate more like the controllers for real RC planes and helicopters. The game pad controllers are around $15-$20 in the electronics and games department at your local retail stores.
Some of these RC flight simulators will also work with your own RC controller as long as your controller has connections for an interface cable (such as USB or serial) that connects the controller to your computer. Others come with real transmitter controllers or cable adapters for various types of transmitters.
Or, you can go to your local hobby store to buy a training controller which has its own training software for flying RC planes. RealFlight Flight Simulators by Great Planes come with thousands of miles of flying fields, flight recording and playback features, add-ons for more aircraft and flying sites, and an InterLink Plus controller that acts as your RC aircraft controller or can be connected to your own transmitter. It has a demo version that is controlled by your computer keyboard. Not great for real flight practice, but it lets you sample the software. Check out it and other RC Airplane Flight Simulators.