Made a full guide that shows how to set up Sixaxis and edit the key mapping so you can play FPS.
https://www.youtube.com/watch?v=VGfYfXPDhFk&feature=youtube_gdata_player
Enjoy!
https://www.youtube.com/watch?v=VGfYfXPDhFk&feature=youtube_gdata_player
Enjoy!