The best I ever found was Black Sun Software's
X-Fonter - really excellent. It's a font mananger as well as a font viewer - install, remove, save, group etc., etc.
It (v6.0) costs money now, but some of the earlier free versions (3.7.6 is the one I have) are still available out on the Web. A quick Google for X-Fonter 3.7.6 shows up a good few sites. Here are a couple:
http://www.freewarepage.de/download/570.shtml
and
http://www.fullprograms.co.uk/descar...-X-Fonter.html
Mac
Edited to add: Just had a quick look at AMP Font Viewer -
http://www.ampsoft.net/utilities/FontViewer.php - looks good, will try it on one of the other machines later.