Boot Gentoo 2005.1-r1 Live via PXE
"These instructions will help you take Gentoo 2005.1-r1 and make a single initrd file which can be booted with PXE. The basic principle is that the squashfs root is put inside the initrd and mounted from there rather than directly from a CD.
Where possible, this will be done without the need to be root on your linux box.
This technique is also used for CentOS_Live PXE."