It's not Perl, or even an open source solution, but there's a product for MacOS called Delicious Library, that I've heard good things about for tracking dvds/music/books/etc. (I've never used it myself).
They use the UPC for tracking items, but I don't know how they've built up their database. You could always start your own -- remember, CDDB and IMDB were pretty bad at the beginning... it took some time for people to get enough info in there for them to become useful. For music, you might be able to seed your database from FreeDB (the open fork of the CDDB database).
