Libellus Personal Library allows you to enter the books you own only by typing the ISBN, either one at a time, or in "batch" mode. It uses web services to download what information is available on the book, and fill the rest in for you. You can keep up with a list of the books you own, your wish list, as well as loan out books, or check in books. You can also print out your inventory or details on a specific book. It is now completely open source, licensed under the LGPL.
