Newer KDE versions have a GUI font installer that can be run from the KDE
control centre. Log in as super-user, with KDE as the desktop. Start up the
control centre from the main panel menu, and then choose System Administration
-> Fonts. While this should automatically carry out the configuration
steps mentioned above, I have not personally used the font installer and
cannot vouch that it works. Unfortunately, GNOME does not yet have a built-in
font installer.