In Building Websites With PHP-Nuke a book published in November 2005, Douglas Patterson has attempted to provide, in his words, A practical guide to creating and maintaining you own community website with PHP-Nuke.
It was brought to my attention by CodyG that my website was mentioned in the book :) so I contacted Doug and requested a copy of the book which he graciously gave me and in return I have agreed to read it and write a review. At first glance it does appear to be one of the better books written on the subject of PHP-Nuke. I will post my review here once I have completed it and submitted it to the publisher.
In addition to http://ravenphpscripts.com getting honorable mention for NukeSentinel™, Chatserv and http://nukeresources.com is mentioned, as well as http://www.karakas-online.de/EN-Book and a few others.
The book is very up to date as he uses v7.8 as his model. It does appear that this book is worth the reading for those needing a good book/tutorial on PHP-Nuke. It will help beginners as well as intermediate users, for sure.