From phpDeveloper site:

"Over on Codewalkers.com today, there's a new note about an offer from the fine folks at APress - a free download of A Programmer's Introduction to PHP 4.0.

No matter what language you are familiar with, this book will benefit you. Beginning with a rapid introduction to PHP's syntax and basic functionality, you will swiftly understand PHP. The book then steers you toward advanced issues, like PHP's role in database manipulation, sessions, and user interactivity.

Author W.J. Gilmore also examines how PHP can work with XML, JavaScript, and the Component Object Model (COM). He loads the book with practical examples and several projects which can be immediately incorporated on any website. The invaluable A Programmer's Introduction to PHP 4.0 shows you how to make the most of PHP's powerful capabilities, regardless of your current scope of PHP knowledge.

Simply jump on over to their page, enter your email address (and yes, you can opt out of the newsletter) and download the book (and the source code to accompany it in .zip) as a PDF document. It's a good starting place for anyone out there that just wants to jump into the basics of PHP. They start from the ground and work up - history of the language, variables, arrays, functions, control structures - even a little object-oriented teaching to round it all out."Note:
I bought this book when it was first released and it was invaluable for me and I have referred to it many times over the past couple of yrears.