gdkxft has made a new release that includes support for Mozilla.
What, exactly, is gdkxft?
"Gdkxft transparently adds anti-aliased font support to
gtk+-1.2. Once you have installed it, you can run any (well, nearly
any) existing gtk+ binary and see anti-aliased fonts in the gtk
widgets. You don't need to recompile gtk+ or your
applications."