[SOLVED]What is this component called and how do I connect it to my arduino?

Hey guys, one of my friends recently gave an arduino with some components.

Among those components I found this:

I'm not sure what it is and how to use it and I have no clue where to connect the 3 pins on my arduino. So I would really appreciate if someone could point me in the right direction.

Thanks in advance :)

This is a potentiometer with a value of 100K. http://en.wikipedia.org/wiki/Potentiometer

It is a potentiometer.

Look here: http://www.arduino.cc/en/Tutorial/Potentiometer

Thank a lot guys :)