A few months back, I participated in reviewing Zend Framework 1.8 Web Application Development written by Keith Pope.
The book is now published and released. You can get it here: http://www.packtpub.com/zend-framework-1-8-web-application-development
This book is for PHP web developers who want to get started with Zend Framework. If you are already using this framework, you will learn how to use it in the best way and produce better applications.
Basic knowledge of Object Oriented design will be helpful.
I haven’t got the chance to read the printed version but hopefully I will be able to within the coming weeks.