This is a neat site.
What is LibraryThing?
Enter what you're reading or your whole library—it's an easy, library-quality catalog. LibraryThing also connects you with people who read the same things.
* Searches Amazon, the Library of Congress and 60 other world libraries.
* Get recommendations. Connect to people with similar libraries.
* Tag your books as on Del.icio.us and Flickr.
* Put your books on your blog.
* Export your data. Import from almost anywhere too.