Books... not so much. I have another idea: you could check out an MVC-framework like codeigniter or CakePHP. There are numerous tutorials about them, and they give you the added benefit of working with an MVC pattern (knowledge you can use in other languages and frameworks as well, such as Ruby on Rails) and working Object Oriented.

In my opinion, a big drawback of PHP is that it's so easy to screw up because it's easy to pick up. There are so many tutorials out there which will let you make a procedural, cross-scripted, sql-injected security liability spaghetti code... Starting with CodeIgniter or CakePHP is not very hard, especially when you have a little understanding on basic programming with PHP. Good luck!