A lot of talk about VORs here, and Fozzer's tangled web...! ::)

Nice-looking panel, though- which 150 is that? ;D
All the above is true and correct, but the part about the ADF always pointing toward the station is the most important. If nothing else, you can just keep that arrow centered, and eventually you will fly right over the station.
As for the dial around the ADF with the markings: there are two types: fixed-card and movable. I have yet to see a fixed card in FS, so...
You can use the movable card for a few different things. Set it so zero or 360 is at the top, and it tells you the position of the station, in degrees, relative to the nose of the airplane. Forces you to do a little math to decide what heading to fly, but you don't have to remember to change it every time you turn, which is part of the other function: finding out what heading will take you to the station. If you keep the card aligned with your DG and/or compass, the needle will point to the heading you want to fly if going to the station.
I also use them ocasionally to get a rough position fix: even in FS9's flight planner, it's pretty easy to guess 90 or 45 degrees by eye alone... you can mark the passing of an NDB station that's not actually on your course by watching the needle deflect as you pass it. This can be useful.... saves the trouble of flying all the way to the station then turning to find the airport or whatever ("I've just passed the NDB; the airport should be just over that hill").