A year or so ago I found this neat little website that allows you to catalog your book collection by entering the ISBN number (or other information if the book is too old for and ISBN). It searches libraries and book sellers around the world then enters the book into a personal catalog for you with information such as author, cover, publication date and publisher and so on.
http://www.librarything.com
The first 200 books are free. You can add an infinite amount of books for $10 a year or get a Lifetime membership for $25! There are blogs and forums for discussing books linked to each book cheese_whine . You can also read or write reviews for your favorites.
The site also allows you to view other people's libraries and make yours available for view if you want using widgets that you can put on your blogs.
I'm Esper_Ranger there...
The Official NaNoWriMo Guild