PS: The German edition includes a short section by me on OA in the US, an abridgement of my longer piece in Neil Jacobs (ed.), Open Access: Key strategic, technical and economic aspects, Chandos, 2006. The English edition includes an abridgement and update (as of September 2007) of the same longer piece.
The open access movement:
Putting peer-reviewed scientific and scholarly literature
on the internet. Making it available free of charge and
free of most copyright and licensing restrictions.
Removing the barriers to serious research.
I recommend the OA tracking project (OATP) as the best way to stay on top of new OA developments. You can read the OATP feed on a blog-like web page or subscribe to it by RSS, email, or Twitter. You can also help build the feed by tagging new developments you encounter.