New Install - need to break up UserSpace partition for /, /boot

[John van Vlaaderen]

Hello, I have an iMac that I want to multi-boot w/ Yellowdawg.

I was getting ready to install are realized that linux doesnt work with 
Mac OSs.

I have a huge HFS -- UserSpace -- drive that I want to split to add the 
boot and / directories.

How do I break up this partition to create /, /boot and UserSpace so 
that OSX will come up ok ??

Looks complicated -- confused here how the OSX mounting works.

TIA, John