If you want MySQL help as well, you should go for "PHP and MySQL Web Development" by Luke Welling and Laura Thomson. It starts with a PHP crash course, then a couple of PHP projects, then fires you into developing database apps with PHP and MySQL. It's a great pace, teaches you everything you need to know as you go along, and then serves as a great reference later. I've had my copy for two years, and still refer to it.
If you want an endorsement, check out the way my site works. Based on only that book, I wrote my own forums software.
I find the PHP functions manual to be very technical, and missing a lot of detail that would help a newer programmer. It's a great reference when you've got some PHP miles under your wheels though.