Recently a post over at TechnoBiblio about using a web site to generate reading interest. I've been recently messing around with using the Amazon.com API as I've been meaning to learn more xml and xsl. One of the mockup's I did was pulling in Amazon book sales data and then linking the results to local catalog searches. Unfortunately my library doesn't carry some of the books and there's no easy way for me to check the backend. Hopefully those limitations are fixed in future versions of the library catalog. I only chose a few categories but it's easily expanded.
Update: Fixed link to mock-up.