In theory would it be possible to control a Servos position with a potentiometer, like in http://arduino.cc/en/Tutorial/Knob but have the potentiometer hooked to one Arduino and the servo connected to a different Arduino and have them communicate point-to-point through wireless with XBees?
In theory, it is possible.
I practice, it works, too. Provided, of course, that you get the right XBees (Series 1), configure them correctly (PAN ID, MY, and DL need to be set to non-zero values, and MY on one must match DL on the other), and write the proper code for both of the Arduinos.