Instructions
Plug one end of the USB cord that came with the controller into the PlayStation 3. The USB ports are on the front of the PlayStation 3.
Plug the other end of the USB cord into the back of your controller.
Turn your PlayStation 3 on. Allow the PlayStation 3 to completely boot.
Press the "PS" button on the controller. This is the button in the middle of the controller. The blinking red lights will turn to one solid light. This means the controller is synced.
Disconnect the controller from the USB cord.