I recently came across LibraryThing, an on-line system for cataloguing your books and sharing the list with others. It is linked to the Library of Congress, Amazon.com, and many other resources, so it has fairly good data for locating your books. I signed up for a free account and entered the first few books that came to view, and it found them all quickly. The only problem I see off the bat is that it doesn’t list multiple versions, so some of my older books will end up displayed under more modern covers.
It looks very flexible, and the author seems to be putting a lot of effort into integrating requested features. When I get a chance I’ll put it to a more strenuous test.