The "Guide to Open Content Licenses" by Piet Zwart Institute Rotterdam was published these days and probably is the first publication to give a systematic, comprehensive overview of the topic from both historic and legal point of view.
The book is published under the Creative Commons Attribution- NonCommercial- ShareAlike- License, and here's where to find it:

PDF: http://pzwart.wdka.hro.nl/mdr/pubsfolder/opencontentpdf
XHTML(+-): http://pzwart.wdka.hro.nl/mdr/research/lliang/open_content_guide