Instructions
Turn off the PS2. Disconnect the microphone from the USB port and plug it back in. Confirm that it is connected properly and secure. Make sure at least one regular PS2 controller is connected as you need one controller to go with each microphone connected.
Turn the PS2 on and start "Guitar Hero: World Tour."
Select "Options" on the main menu. Select "Microphone" and adjust the incoming voice level until the microphone picks up your voice at normal speaking levels.