There aren't any good php books out there. The basic books mostly mimic the php.net manual, and the so called "advanced" books really have questionable techniques.
The three best ways to learn php:
Follow this board and see how various problems are solved... often in more than one way.
Check out a couple of code boards. Review the source to see how a task was accomplished.
Decide to write an app with a specific function... simple to start... then test and play until you get a sense of the language.