Don't worry about PHP6 yet, its a long ways off and there will be plenty of up to speed type books when it releases. For where you are at, online tutorials are your best option. Reason being that you are at a level where there are almost endless subjects to cover, far too broad for any book.

As far as OOP goes, I've come to believe it can be learned from a book, but only mastered though use and experience. If you understand how OOP works, just keep using it and things will become more clear as you go on.

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