Computer-readable potentiometer
You can measure the voltage with one of the Analog inputs of arduino (pay attention that the maximum input is 5V so if your voltage is higher you should reduce using a voltage divider).

Then you can send the readings to the pc using the serial comunication through the usb port.

You will need than a software that reads the data from the USB port, I have done it many times using python, but any programming language or software can be useful.
If you are interested I can send you some code snippets.