I recently buy a good catalogue software via the internet called DVDPEDIA.
From the creator:
“DVDpedia is a movie cataloging application for Mac OS X.
To save you time and effort, it retrieves all the information from the Internet via keyword or UPC scan, so you have time for more important things, like watching movies.”
It have also a rent reminder function: if you borrow DVD’s to your Friend’s and have (I hope) a lot of friend, the software remind via email to them that the rent is over after a configurable period.