I don't think you'll find any easy config options for that. I believe the way to go about it is via the file .Xmodmap which *might* be in your home directory, or in /usr/X11R6/lib/X11/.Xmodmap.
Looks rather confusing to me, and I haven't found a good, simple tutorial, but for starters, go in a console and type 'man xmodmap' and 'man keymaps', and read those pages..
And... Use Google