antonio104 mentioned a "USB cable" from TTI.
Note that, despite using USB interface, it's just a PIC serial cable in disguise--it has an on-board USB-to-Serial converter, which does not change the fact that very few simulators support it:
[link=http://www.milehighwings.com/sim_compatibility.htm]www.milehighwings.com/sim_compatibility.htm[/link]

A true USB interface is visible in Windows control panel as a multi-axis joystick, it can be used by any software supporting joysticks.

Just my 2 cents...