I've been after a decent poster Cataloguing tool and I noticed most people use photograph programs to catalogue their collections, They didn't quite cut it for me so after a search I found "Movie Collector" a program designed to catalogue your dvd\bluray\media files. It has api so you can just type in your movie poster name and it will download all the relevant data, then just manually add your poster details and picture>
It even adds youtube trailers
Anyone wanting to know more about this program should go here>
http://www.collectorz.com