How do I create a keyboard layout?

[Nando Florestan]

Short version: I need to create a keyboard layout but I don´t know
where to start. What should I read to learn about this? There seem to
exist at least 3 different places for keyboard layouts: the console,
the X window system and Gnome. Of course I would like my keyboard to
"work" on all of these...

Long version:

Most Brazilian people use a keyboard layout called ABNT2. Very few
people here know about the advantages of the Dvorák layout and even
fewer use it.

So I have made a keyboard driver (for Windows) for a layout that
consists of a rearrangement of ABNT2 keys resulting in a Dvorák
keyboard layout appropriate for Brazilians:
http://oui.com.br/n/content.php?article.17

Now I wish to implement the same layout in Linux, but I am having
trouble determining the least painful way to do it. Does anyone know
about keyboard layouts?

-- 
Nando Florestan
http://oui.com.br/n/
MSN: nando2003 at mandic.com.br
ICQ:  15848487
Jabber.org: nandoflorestan