For a screenshot see: http://carlos.pemas.net/blog/200401030430

If this makes it before feature freeze, I think we should use this list
instead of our own (Prefs->Language->Language section).
With the language section removed, the last page of our prefs dialogue is
pretty empty, maybe we could use the remaining two combos to the first page
(they are "Default encoding" and "Autodetect encoding")?

First patch attached removes the language section. As soon as I know which
gconf key and format the gnome languages list uses, I'll add a second patch
to mozilla-notifiers.cpp using it.