how to use *.pfb-fonts?

[Max Moritz Sievers]

I want to use the freefonts from the contrib-directory. These fonts are 
pdf-fonts like those in /usr/X11R6/lib/X11/fonts/Type1/ but I can't use 
them in Gimp (and any other application) (after copying them to this 
directory).
Gimp displays only the fonts in /usr/X11R6/lib/X11/fonts/100dpi and 
/usr/X11R6/lib/X11/fonts/75dpi.

Regards,
Max Moritz Sievers