Mordecai's original link is to a book published by WROX, an excellent publisher. Most of the others listed underneath are rubbish: that is why there are so many used copies available. At best they are just out of date. Avoid anything by SAM'S, they used to be a good publisher 10 years ago, not any more.
I personally would recomend Kevin Yank's articles and books at Sitepoint. The link is to his book that is ideal for a beginner, and you can download several chapters that will get you started.
Bookmark Sitepoint and subscribe to their newsletters and forums. They let you download sample chapters from many of their books so you know what you are buying, and their stuff is generaly up to date, a very important point with PHP as it is developing so fast. I see a lot of posts from people having trouble because the book examples and tutorials they are using are out of date, and many were rubbish even when they were current.