When the CHUD tools are properly installed and the machine is rebooted, there will be a new preference pane called "Hardware." Select this one and uncheck "Nap." This will (usually) silence the G5 chirping sound that many people have (particularly dual-processor machines).
Be aware that it has been reported that Apple does not recommend disabling "nap," though no one has yet to report a problem, and additional heat doesn't seem to be produced.
Edit: At least as of version 3.02, you have to uncheck the Nap box in the Hardware pref pane after each boot. I've not installed 3.04 (...if it ain't broke...). Today, version 3.5 was released.