How to change Facebook theme !

Styles
✔ Aero
✔ Black & White
✔ Dark-N-Grey
✔ Dark Shiny Blue, Transparency
✔ Dark Shiny Purple, Transparency
✔ Dark Static, Transparency
✔ Hello Kitty
✔ Hot
✔ Nalvin Style
✔ Naruto
✔ Pink
✔ Pink Love Is Everything
✔ Purple Hearts
✔ Sky Background
✔ Snowy Mountains
✔ Stars
✔ The Simpsons
✔ Xbox 360 (green, white & orange)
✔ WINDOWS 7 Abstract
✔ Windows 7 Black Edition

How-to
To change facebook theme you must install Facetweak Facebook addon to Firefox. Easy installation is given below, just click "Add to Firefox", then read instructions and continue.
Yes this only works for Firefox but not IE, Opera, Safari.