It is now possible to access Open Library book metadata in an RDF/XML format. The access is through the RESTful API. For an example, view:
http://openlibrary.org/b/OL6807502M.rdf
The returned RDF/XML relies heavily on Dublin Core metadata terms, and uses some elements from bibliontology and the registered RDA schemas. Although soundly based on RDF, the output can be used like any XML and presents (most of) the Open Library metadata in the easily understood Dublin Core terms.
It has been suggested that this format include links to cover images, where available. It is also on our list to add tables of contents to the output. Other suggestions are very welcome — add them here, or send them to the ol-tech discussion list.
We’d love to hear about the uses you make of this API, and anything we can do to help you get more out of the Open Library.