I was doing some php research yesterday and stumbled on this online php book that had some very good information and examples that I could put to use right away. Check it out at http://www.tuxradar.com/practicalphp It's all online in html format, so there is no PDF etc. but it is easy to navigate with links to previous and next chapter as well as a "Jump to" drop down and a link to the table of contents.
The book has been updated for php 5.2 so it is kept fairly current, which is always a plus with online content!
So, if you are looking for good, free, text on php stuff, check this book out - it doesn't cost you anything:)
Arnor Baldvinsson