[Al Skierkiewicz]

So as not to confuse others reading this thread...
You can use a pot at the OI for input to your control system for modifying the speed and direction of the motor in much the same way as a joystick (which contains pots on two axis). See the OI Ref Guide on the IFI site for info.
Many teams also use a pot connected to the motor or shaft of the actuated attachment driven by the motor. This pot is used for feedback to allow the software to know where the actuator is or how far it has to move to get where you want it. The info for connecting this pot is contained in the RC Ref Guide. You may also use this pot as a sensor input to a custom circuit mounted on the robot.