a clarification, there is a software hack which effectively is an xbe program functioning as the boot loader on Xbox that can load vmlinuz/initrd and turns Xbox into basically a normal PC.

There is also a KNOPPIX like distro called Xebian that also runs from CD-R(well CD-RW) using the same concept of KNOPPIX, clooped block device(to squeeze more into the CD) and symlink stuff so it is again a boot and forget system, without touching the HD.

The site is http://xbox-linux.sf.net, xbox-scene is for generice xbox stuff(exploit, hacking etc.). You can find more information the software exploit there though.