Check out the instructions from coofercat...
http://www.coofercat.com/wiki/CustomFedoraBootableCD
Here is part of what I used.
Code:
mkdir /home/boot
mkbootdisk --iso --device /home/boot.iso `uname -r`
mount -o loop,rw /home/boot.iso /home/boot
You'll find nothing but an isolinux subdirectory, which you should copy into your "CD system". After that, you're done with the image, so unmount /home/boot and delete /home/boot.iso.
mkdir /home/bootcd
cp -R /home/boot/isolinux /home/bootcd
umount /home/boot
rmdir /home/boot
rm -f /home/boot.iso
isolinux.cfg
default linux
prompt 0
timeout 0
label linux
kernel vmlinuz
append initrd=initrd.gz ro root=/dev/hdc
This will instruct isolinux to look to /dev/hdc for the root of the system,
where it will also find the initrd image.