Installation for XFree86 (X.Org)
--------------------------------

Unpack the archive file containing fonts in some temporal directory, for
example /tmp :

cd /tmp
tar xzvf cm_unicode-VERSION-pfb.tar.gz
cd cm-unicode-VERSION

where VERSION is version number of this font pack.
Then create cm-unicode/ directory at the place, where your X stores fonts, for example 
/usr/share/fonts :

mkdir -p /usr/share/fonts/cm-unicode

You should become root to do it. Then copy font files there:

cp *.afm /usr/share/fonts/cm-unicode/
cp *.pfb /usr/share/fonts/cm-unicode/

If you are using XFree86 prior to 4.3 you shoul also copy fonts.scale there.
Then change directory to /usr/share/fonts/cm-unicode/ :

cd /usr/share/fonts/cm-unicode/

and do

mkfontscale # if you are using XFree86-4.3 or later or recent X.Org
mkfontdir

Currently mkfontscale and mkfontdir may produce errors, so copy
fonts.dir and fonts.scale files supplied into 
/usr/share/fonts/cm-unicode/

Then add  
FontPath     "/usr/share/fonts/cm-unicode/"  
to "Files" Section of /etc/X11/xorg.conf (/etc/X11/XF86Config). On the
next run X.Org (XFree86) will load these  fonts.

If you are using fontconfig (X.Org, XFree86-4.3, may be installed on 
XFree86-4.2) you should add a line
<dir>/usr/share/fonts/cm-unicode</dir>
to /etc/fonts/fonts.conf or better to /etc/fonts/local.conf then run

fc-cache


Installation for ghostscript 
----------------------------
(Optional, modern versions of ghostscript retreive information from fontconfig)


Assuming that you have rather new ghostscript version like 7.x go to
default ghostscript font directory, typically /usr/share/ghostscript/fonts, then
add links to fonts installed for X or copy them:

cd /usr/share/ghostscript/fonts
ln -s /usr/share/fonts/cm-unicode/*.afm .
ln -s /usr/share/fonts/cm-unicode/*.pfb .

Then go to the ghostscript library directory, for example 

cd /usr/share/ghostscript/?.??/lib

where ?.?? is ghostscript version. Copy Fontmap.CMU from tarball:

cp /tmp/cm_unicode-VERSION/Fontmap.CMU .

Then add following line to Fontmap file:

(Fontmap.CMU) .runlibfile

Note that pdfwriter from ghostscript versions prior to 8.x does not
understand characters not existing in the encoding. These fonts were
tested with ps2pdf script from AFPL ghostscript-8.14.

That's all.