Hi all I saw this: http://about.ck12.org/ the other day, it's a collection of CC-BY-SA textbooks for k-12 (although mostly secondary school there at the moment) thought it might be of interest. My general comments on flexbooks are here: http://brendanscott.wordpress.com/2009/08/27/flexbooks-a-non-braindead-way-to-produce-textbooks/ Regards Brendan