gofaster...
Go to your local Radio Shack. For just under $16 they have what you are looking for. It is very versatile, and can emulate 4 switch selectable modes; gamepad, joystick A, joystick B, and wheel. The two joystick settings are for TM type and CH type I believe, and this is explained further in the manual that comes with it. Prior to upgrading to my current X45 setup, I used it with my old Quickshot Sky Commander HOTAS setup. This was old and pretty low tech, but the adapter smoothed out the spiking VERY nicely. The adapter you need is catalog # 26-164, Gameport to USB adapter. As far as I know, its adjustability should allow it to work with just about any setup you would need. Good luck!