FMS Interface
Why to spend $40 on FMS-only interface? For this money you can buy a TX-to-gameport interface, which acts as a joystick in any Windows, including XP.
The difference is that you can buy almost any R/C sim and use the interface with it. I've heard that CockpitMaster is rather inexpensive (about $40 to download?) and, at the same time, pretty good.