Instructions
Download the SIXAXIS Controller driver from the link below in References. It comes as a RAR file, so you'll need to unpack it.
Plug the PS3 controller into your computer with a USB cable.
Run the executable file named "ps3sixaxis_en.exe" and wait for your system to recognize the controller. If it doesn't after a few moments, press the PS button.
Configure your PS3 controller for use with PC games and emulators. Each game does this differently, so you'll need to consult your game manuals for specific instructions.