I'm trying to find a 4 position switch to use with an arduino project.

The first position would be off, as in no power to the arduino. Positions 2,3,4 would all provide power to the arduino and I need to be able to tell which position the switch is in. Think of

OFF-LOW-MED-HIGH

What sort of switch would accomplish this, and how would I wire the power and the pins to the digital pins on the arduino?