O'Reilly Publishing has just released a new PHP book for those looking to get to the "heart of the language" the fastest - PHP: The Good Parts.
Get past all the hype about PHP and dig into the real power of the language. This book explores the most useful features of PHP and how they can speed up the web development process, and explains why the most commonly used PHP elements are often misused or misapplied. You'll learn which parts add strength to object-oriented programming, and how to use certain features to integrate your application with databases.
You can see the full table of contents on their page for the book including beginner topics like functions and variables all the way out to security, advanced goodies and PHP 5.3.