Sams Teach Yourself PHP in 24 Hours
by Matt Zandstra
That's the book that taught me PHP... and some of my friends in college...
But that's just to get you into it... after a while you'll need to do more stuff and with the help of php.net you'll learn more on your own...
Oh... and I code PHP for a living now
(I never get tired of saying that, I love PHP)