I'm not clear if you are planning on using your pc as a controller, or designing a seperate board that is controlled by the pc.
If it's just reading the knobs on a pc that is causing you headache, I would suggest that you look at the game port of old machines. You can still buy usb to game port adaptors. The gameport uses a monostable that provides different pulse widths depending on what resistance is across one of the axes inputs. I know the old apple2 required pots that reached either 100K or 150Kohms. for the pc gameport requirements.
If it's a seperate controller that you are thinking of, then take a look at the PIC controllers from Microchip Technologies. Some of the PICs have analog inputs.