Erase hard drive

I have a MacBook G4 which I no longer use. How can I erase the disk to remove all my data? alternatively, how can I access the disk to physically destroy it?

Boot from your install disk and... ah here's a tutorial:

How to securely erase your mac hard drive before selling it. | MacTip.net

Erase hard disk

Thanks for your quick reply and apologies for not acknowledging it sooner. I've been out of action for a bit. Your solution sounds a bit complicated for my skills level, but I'll look at it more carefully and give it a go. Thanks again.