David Santos is making Openmathtext.org even more open by permitting rather than blocking commercial use. According to Open Text Book:
...[H]e’s agreed to gradually phase out use of the Open Publication License with the noncommercial option, and to start using a license compatible with the Open Knowledge Definition.
Several of the books on the site’s download site are now available under the GFDL, including:
Elementary Algebra Lecture Notes
Precalculus I and II Lecture Notes
Linear Algebra Notes
Number Theory Notes...
Posted by
Peter Suber at 12/21/2007 09:40:00 AM.
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.