Generally, I'd say that a book is your best bet, but here I'm gonna have to agree with vincent.
No PHP book I've ever purchased comes close to the examples here.... also, for function reference you can't go wrong with php.net (same docs as here, but with user contributed notes).
However...if you DESPERATELY need a book (ie. if you really have no background whatsoever in programming and feel that a book will help you) then "PHP programming" by New Riders Publishing is a great one. Too bad it isn't free, like everything i mentioned above.