- The book will be licensed under the GFDL and an online version will
be available. (No Starch has been a great partner in this and has been very supportive of open licensing). Where the book reprints on-wiki documentation, the authors of that documentation will be credited.
Have you considered Wikibooks for this? Wikibooks does allow books about using Wikipedia and there have been attempts in the past to write books about Wikipedia on Wikibooks. Many of these books have been abandoned by their original authors, sadly. If you have drafts of extra information that isn't going into the book, Wikibooks would love to have it.
--Andrew Whitworth