I haven't tried it, but take a look at isbndb
API Description: Introduction
ISBNdb.com's remote access application programming interface (API) is designed to allow other websites and standalone applications use the vast collection of data collected by ISBNdb.com since 2003. As of this writing, in July 2005, the data includes nearly 1,800,000 books; almost 3,000,000 million library records; close to a million subjects; hundreds of thousands of author and publisher records parsed out of library data; more than 10,000,000 records of actual and historic prices.
Some ideas of how the API can be used include:
- Cataloguing home book collections
- Building and verifying bookstores' inventories
- Empowering forums and online communities with more useful book references
- Automated cross-merchant price lookups over messaging devices or phones
Using the API you can look up information by keywords, by ISBN, by authors or publishers, etc. In most situations the API is fast enough to be used in interactive applications.
The data is heavily cross-linked -- starting at a book you can retrieve information about its authors, then other books of these authors, then their publishers, etc.
The API is primarily intended for use by programmers. The interface strives to be platform and programming language independent by employing open standard protocols and message formats.