They also improved the zend engine, CURL extension, added Tokyo cabinet abstract and Berkeley DB Support! Added a couple of hashes, Improved JSON Extension (JSON_NUMERIC_CHECK!) and a whole lot of bug fixes. The UTF-8 part was long overdue, glad they fixed that.
I spend a lot of time programming in PHP. Its reputation is pretty bad, but updates like this keep me going!
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!
CodeIgniter and CakePHP are great examples of code badly brought forward into PHP5 from PHP4 roots. I wouldn't recommend either to either a novice or an expert; CodeIgniter is a fantastic example of out-of-date practices and CakePHP an example of writing such abjectly slow code that everybody else benchmarks against you to look good.
If you're going to use PHP5, Symfony2 is a well-reasoned, best-of-breed system.
I'd also recommend Kohana. It was originally a fork of CodeIgniter, but version 3.0 was a complete rewrite for PHP5. Compared to Symfony, it's more of a barebones framework.
I wouldn't. Kohana's track record of cavalier response to security concerns is off-putting and their code is not particularly impressive.
There's a reason people who use PHP are getting on @fabpot's train and not Kohana's, and that's because Symfony2 does much, much more right than anyone else in the conversation.
I spend a lot of time programming in PHP. Its reputation is pretty bad, but updates like this keep me going!