input needed for a mini How-To on "multiple independent X sessions/ X users"

Hi,
i'm trying to write a mini How-To on configuring a system for multiple X users,
it's quite unfinished and in order to finish it, i need all kind of input
(corrections, missing parts,examples, ...) from all users of such systems.

like i said, it is centered on configuring the system, not hacking the kernel or X
and i hope once ruby runs, the How-To to became 
"Running multiple independent X sessions under linux useing ruby/ backstreet ruby"
and not like now to be related only to backstreet ruby.

The url is:
http://varna.demon.co.uk/~svetlio/aivils2/contrib/miniHow-To.html

Regards,

Svetoslav