It all depends on which sims you intend using the USB adaptor. All the commercial R/C sims available today, will most propably require it's own dedicated interface.

The USB interface installs as a standard Windows joystick, and will work on all games/simulators that have joystick support. Most of them will have the same functionality, with at least four proportional axis. Most USB interfaces make use of the rest of the available rx channels to represent fire buttons, that can be used for flaps, gears etc.

I can recommend the interface from [link=http://www.rc-circuits.com/]R/Circuits[/link]. He is in Canada, but you will not have any problems with his interfaces. Have a look on [link=http://myweb.absa.co.za/eric.brouwer/interface.htm]my web[/link] for more links to suppliers.