The Sept./Oct. 2011 (vol. 40, issue 1) issue of Knowledge Quest, the publication of the American Association of School Librarians, is all about educational gaming. The table of contents is online, but to get the full issue, you will need to get the journal through your local library or AASL.
I am able to share a preprint version of my article from that journal with you here. It is called "Making Gameplay Matter: Designing Modern Educational Tabletop Games," and you can find it at: