Things You'll Need
Instructions
Connect your "Rock Band" controller to the PS2 to USB converter. These can be found in most online marketplaces that sell game products, such as Amazon.com. Most adapters allow you to plug in up to two controllers at the same time.
Connect the PS2 to USB converter into your computer. Plug the USB adapter into a USB port on your computer. Ensure you have installed any necessary drivers for your converter to work properly. Most times this is unnecessary if the device is recognized by your computer.
Download a key mapping utility. This will enable you to easily bind keystrokes to buttons on your game controller. For example, you can bind one of the guitar's buttons to execute the same action as when the spacebar is pressed. Two popular key mappers are JoyToKey and Xpadder.