The USPTO and EPO have released the new Cooperative Patent Classification system ahead of the January 1, 2013 implementation date. Details are available at the CPC website. Documentation includes the entire CPC scheme, an initial set of definitions and CPC concordances.
I'm the librarian for research services in the Engineering and Science Library at Queen's University in Kingston, Ontario. I've been working with patent information since 1991, including seven years at the U.S. Patent and Trademark Office. I believe that the dissemination of patent information is a public good and should be promoted, especially in the education of science and engineering students.