http://www.presonus.com/faderport.html
It doesn't have any driver "installed in system" that I know (yet) it is coming with my presonus firestudio project (shipping)
It uses component files (like a *.dll for cubase) which has to be included in the application somehow, so I guess FL has to support that...don't know yet for sure.
I think the faderport is a nice addition in my setup since it has transport controls and some ways to make life easier while sequencing/recording/automating
more research -
1.5 INSTALLATION GUIDE
PC and Mac:
1.) Connect the power supply and USB cable to your FaderPort, and the other end of
the USB cable to any USB connector on your computer.
2.) Windows/OSX will automatically install the class compliant drivers for your
FaderPort. You may need to wait a few seconds for your computer to recognize and
load the FaderPort USB device.
3.) Skip to the appropriate setup section for your DAW.
Here's the manual just in case:
http://www.presonus.com/pdf/faderport_manualver1.pdf