So, here's what I've done so far...
I ran xev to find the keycodes for the extra keys on my Microsoft Natural
Pro keyboard.  Then I edited xmodmap.std and added those keycodes.  I can
now get the extra buttons to output things like the letter 'a', but I'd
like to have it output something like Ctrl-Right or Ctrl-Alt-F4 when I
press these keys.  Any ideas how to do this?  My ultimate goal is to
accomplish in Linux what the keys were meant to do in Windows.  So, for
example, I'd like to have the "Web" button launch Konqueror and I'd like
to have the "Back" and "Forward" buttons navigate through Konqueror, etc.
I can setup the keybindings in KDE, I just need to figure out how to get
one key to output several other "keys."

Thanks,
~M