Things You'll Need
Instructions
Purchase a PS2 to USB controller adapter. You can buy these on the Internet and from certain electronics retailers. Generally, one of these devices should cost no more than $5.
Plug the end of your PS2 controller in to the USB Controller adapter. The adapter itself has three input ports: Two PS2 controller input ports are used for plugging in controllers; the other, a USB output, used for plugging the controller in to your computer. Plug the USB end of the device into a USB port on your computer.
Plug your PS2 controller in to one of the controller inputs on the PS2 to USB device. There will be two---one for player one, one for player two in a multiplayer game setting. If you're using only one controller, plug it in to the input labeled "Player 1." You are now ready to use your PS2 controller to play games on your computer.