Install to existing multi-boot partition?

Hi all,
I have a laptop which is already set up for multiple boot (RH9, using grub); which files do I have to copy/change to a) put the KNOPPIX fs onto the hard drive, and b) make booting into KNOPPIX one of the options under grub?

I'm somewhat familiar with what's in /boot, but I'm not sure where the rest of the stuff goes. Also, I have space on the partition (ext3) holding the other os's, but also have a 2GB FAT partition; I just don't want to remove or screw up my existing grub stuff.

Thanks.