[CentOS] Howto reconfigure / rebuild CentOS 5 LiveCD

Hi,

I like to add some of my own utilities, etc.. to the CentOS 5.0 LiveCD.
IOW I am looking for a way to rebuild the livecd for specific purposes.
Can someone reach me handle where to start?
The only thing I've found so far is the out-of-the-box iso.

Thanks,
John