I originally learned alot about php from sitepoint and purchased thier book from thier website which covered alot of thier online tutorials and went into additional detail and examples. It was a good book I think especially if you were getting started.

I just picked up Sams PHP in 24 hours (picked up Sams XML in 24 hours too while I was there lol) since I wanted to brush up on some things. I looked at Larry Ulmans book which was also nice and so was the Begginers PHP book. It was a hard choice but I went with Sams in the end simply because it was the most recent.