If you are waiting for Dave Snowden's book you may have to wait a little longer. He told the audience at KM World not to email him over the Christmas period as he planned to complete it then but its been in the making a long time and so I wouldn't hold your breath.
But in the meantime maybe you would like the next best thing - the November 2007 issue of the Harvard Business Review (HBR) carries an article by Dave and his co-author Mary Boone titled A Leaders Framework for Decision Making.
The article is about the Cynefin Framework and you will find a review has been written by John Caddel. Jay Cross has also posted a blog entry which includes a rather serious looking Dave with pint in hand at the recent blogger beer bash at KM World in San Jose.