1. PHP 5 in easy steps (Book)
I have used elements of this book in other projects and has proven to be an invaluable as a beginner to the language.
2. The PHP Anthology (Book)
I purchased this book at the same time as the CSS Anthology from Sitepoint. This book could be considered as a reference book rather than a tutorial / walk through.
PHP.net is a fantastic resource containing tutorials & reference material as well as links to related sites.
MySQL.com provides support spacifically tailored for MySQL use including forums & manuals.
W3 Schools is a well respected & established tutorial (and forum) web site; this section of the W3 Schools focus on PHP.
PHP tutorial & reference web site. The web site also has a supporting forum.
HTML Goodies delivers more than just advice on HTML & CSS; this area of the web site delivers tutorial based advice on working with PHP.
This web site delivers great PHP tutorials along with examples of source code to visualise the learning.
Kill PHP contains text & video PHP tutorials aimed at beginners.
PHP 101 - PHP for the absolute beginner.