Here are two superb wiki-based collections of digital library projects. It's a fair assumption that most of the listed projects are OA, although their access status is not indicated in either collection. Both lists are user-editable. If they're missing a project that you know about, add it.
DigiMisc from Klaus Graf is organized both by field and country. The annotations are in German.
Posted by
Peter Suber at 8/29/2005 04:11:00 PM.
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.