WordPress Books or Resources?

Hey guys, I used Joomla! for the majority of websites I develop. Recently, I have had an increase in websites that have blogging capabilities. And although Joomla! can handle blogging well, I want to make it as easy as possible for my clients that are less internet savvy.

SO that being said can you guys recommend any beginners guides or resources? Preferably something geared toward individuals with existing web development knowledge?