If you've done this before I would appreciate you walking me through what has to be done for this to work so that we can have a guide for people to use. We're getting a lot of people asking about PS3 controllers in the YouTube comments.
I got my ps3 controller to work with a tool called "DS3 Tool". Notice the big "T", I was told that there's a simmilar programm which has a small "t" in its name and wich isn't half as good.
The tool I use however is pretty much self-explanationary. After installing it I just had to press "enable" and the buttons were mapped automatically. There also is a tutorial on what to do if that doesn't work but I don't know where it was.