Does anyone have any good book recommendations on design patterns, and applying them in PHP?
My two recommendations would be Matt Zandstra's excellent PHP5 Objects, Patterns and Practice and the equally excellent php|architects guide to PHP design patterns
I don't think it is necessary to get a PHP specific design patterns book, as the concepts mostly language agnostic. Ex. once you learn the concepts of the strategy, composite, or the observer pattern, and once you've seen an example of an implementation in any humanly readable language, implementing it in PHP is really trivial. The only major difference (compared to say, Java) is that PHP is a dynamic language; therefore, polymorphic behavior is achieved via duck typing.
Instead of purchasing a PHP specific design patterns book, I suggest you get Head First Design Patterns, this book explains the concepts in an interesting, and arguably humorous way. Once you read this book, you should be well off on implementing patterns into your applications.
If you already understand the concepts of OOP, check out this design patterns and antipatterns gallery, if the code samples on there make sense to you, then definately get the book I mentioned.
you can also checkout this site http://www.phppatterns.com/docs/?idx=design , it has good examples of the patterns in use also