Here is a freeware one:
http://www.lyrasoftware.com/index.php?option=com_content&view=article&id=23&Itemid=64&lang=en
Here is a list of some others as well:
http://www.techsupportalert.com/content/best-free-file-disk-catalog-organizer.htm
I used to used one called diskdb, but it's not freeware anymore. Haven't used anything like this in awhile.