used a Gravis Game Pad for my PC. It has two thumb sticks and you can set it up just like the controls on your radio
I've been in Best buy and held the game pads...almost bought one for this very reason!...just didn't know if it would work or not. The sticks are a perfect simulation of a Tx...this is certianly a great alternitive!!!...download FMS, run to best buy, and your flying in less than an hour for very little $$