After thinking about setting up a books database on my computer using Booxter, along comes a Web-based flickr-style version called LibraryThing. Designed by Tim Spaulding, it uses ISBN, bar codes, Amazon, and straight ol' manual input to create a db on the web to represent your collection. You can then link to it and show people that, in fact, you have way too many Star Wars Universe novels for a 35-year-old man.
As you can see, I've already signed up, entered a few books--from my reading pile at work--and installed their blog widget on the left-hand side. Ain't it amazing?