Numento - With Numento, you will be able to efficiently and easily manage your collection.
Readerware Book Database - The easiest, fastest way to catalog your books, nothing else comes close.
CollectorAce - CollectorAce is a web application to organize and catalog all your library - books, comics and magazines.
Tellico - Tellico is a KDE application for organizing your collections.
Delicious Library - Delicious Library 3: Catalog your books, movies, music, software, toys, tools, electronics, & video games. Archive your life.
Book Catalogue - This is a simple book catalogue application, to store a list of your books.