Ten Security Checks for PHP (ONLamp)
Though it's easy to create sites in PHP, it's not immune to sloppy coding. Clancy Malcolm explains how to recognize and fix potential security holes.

Database Enabled Websites
A tutorial on using PHP3 and MySQL to develop database enabled applications for websites.

Gimpster
Introductory tutorial geared towards those with little to no PHP experience.

Website Publisher - Using Cookies in PHP
Learn how to set and read cookies using the PHP scripting language.

Website Publisher - Saving Resources with phpCache
Tutorial explains how to implement the phpCache script and use it to keep your database server load low.

Website Publisher - Search Engine-Friendly URLs
Article describes three ways to make your URLs search engine friendly using PHP.

PRCE: Perl Compatible Regular Expression In PHP
Article on perl compatible regular expressions. Describes the basics as well as PCRE's special features such as ungreedy matching, lookaheads or the evaluation modifier.

How To Compile PHP 4 and Apache 2 from Source On Linux
Provides detailed, step-by-step information on compiling PHP 4.2.0 as an Apache 2.0 shared module on a Linux system.

PHP/MySQL Tutorial
The lessons provided in this PHP/MySQL tutorial are short and simple. You'll learn to create and manipulate a simple database of names and birthdates.

Classes and PHP (PHPBuilder)
A description in plain English of what classes are, and how they can make your project easier to complete and extend.

Comprehensible PHP Code (PHPBuilder)
A good programmer makes her code look so simple and comprehensible that any other programmer can understand it and appreciate it.

Error Handling: Stepping beyond True/False Results (Zend)
This article teaches you to handle errors in an elegant manner, and looks at how to handle PHP script errors as well as passing around your own errors with the PEAR module: PEAR Error.

Static Free Energy (Zend)
This tutorial will show you how to produce static html pages using PHP. This is important if you want the benefits of using PHP to build sections of a site where the content of the pages doesn't change very often.

An Introduction to Classes (Zend)
The tutorial guides you through the construction of a simple, security-related class that performs some basic security functions for a web site: checking user logons.

Encryption and Decryption using PHP and GnuPG (Zend)
The purpose of this article is to show you how to encrypt and decrypt information with GnuPG using PHP. Most of the major Linux distributions will install GnuPG upon request. Otherwise you can get it by going to http://www.gnupg.org.

PHP Manual
Complete and hyperlinked manual documents and explains all elements of PHP. Includes FAQ section and user comments.

PHP and Regular Expressions 101 (WebReference)
This tutorial steps through the POSIX-compliant regular expression functions in PHP in a straightforward manner.

caiPHP
Tutorials and code snips directed to those who are learning PHP.

Template Example with PHP Includes
Show how to use 'php includes' inside a template.

PHPExamples.net
Tutorials, code snippets regarding PHP. Forums.

Open Source Licensing For PHP Scripts
Open Source licensing for PHP scripts. Open Source means that your software is entirely free for use, to anyone, and any user may modify the software to fit his own needs. To launch an open source application, you have to apply the GNU GPL License.

Simple Introduction To Classes
By the end of this tutorial, you'll have a better understanding of what classes are and what they are good for. Classes can be very powerful when used right and can save you a lot of work (and typing) in the long run.

Installing Apache, PHP, and MySQL
An indepth article that offers a step by step guide on setting up a home server for website development and testing.

PHP Programming Goodies
PHP programming tips and tricks.

Pitfalls of Transactions with PHP (ONLamp)
Database transactions are important for data reliability and consistency. Used properly, they can prevent many types of errors. Used improperly, they can cause many other kinds of errors. Kimberlee Jensen demonstrates using transactions with PHP well.

Configuration Manipulation With PHP Config (Dev Shed)
This article introduces a toolkit designed specifically for manipulating configuration files, thereby reducing the number of lines of code needed to read and modify application variables. This toolkit is written in PHP and implemented as a class, suitable for use in any PHP-based application and accessible via standard OO techniques.

Database Abstraction With PHP (Dev Shed)
Take a look at the PEAR database abstraction layer, one of the coolest PHP widgets out there.

File And Directory Manipulation, Part 1 (Dev Shed)
PHP comes with a full-featured file and directory manipulation API that allows you (among other things) to view and modify file attributes, read and list directory contents, alter file permissions, retrieve file contents into a variety of native data structures, and search for files based on specific patterns. This file manipulation API is both powerful and flexible - two characteristics that will endear it to any developer who's ever had to work with file manipulation commands.

File And Directory Manipulation, Part 2 (Dev Shed)
This second segment of the tutorial on the PHP filesystem API takes you into deeper waters, showing you how to copy, delete and rename files; scan directories; work with uploaded files over HTTP; perform pattern matches on file names; and read and write to processes instead of files.

Installing Apache, MySQL, and PHP on Linux
This tutorial is designed to guide through the initial steps of setting up Apache, MySQL, and PHP on Linux.

Build your own Web Service with PHP and XML-RPC
Harry takes us one step further into the world of Web Services. Here he explains how to build your own Web Service - a news feed - using PHP and XML-RPC.

Microcyb's CyberCMS Web Development PHP Tutorials
Collection PHP tutorials with code examples.

Blobbing Data With PHP and MySQL (Devarticles)
Showing how to store and retrieve binary data in a MySQL database by using PHP.

Getting Intimate With PHP's Mail() Function
PHP's Mail() function is a great way to send mail using a simple and standard interface that hides the complexity and quirks of various system programs that are responsible for sending mail. This tutorial will introduce you to the basics of sending mail from PHP scripts.

Ben's PHP Tutorial
Simple tutorial that introduces people to the world of PHP software development. Topics covered are variables, arrays, forms, files, SQL databases, etc. End of tutorial demonstrates a full PHP application with source.

Tizag PHP Tutorial
A PHP tutorial that covers all the basics of PHP. It is geared towards web developers with little or no PHP experience.

Simple Linear Regression With PHP
In contrast with other open source languages like Perl and Python, PHP lacks a robust community effort to develop a math library. This article provides an example of a PHP math library called SimpleLinearRegression that demonstrates a general approach that can be used to develop PHP math libraries.

Implement Bayesian Inference Using PHP
Conditional probability -- the probability of observing one event as a result of having observed another event -- is a potentially important factor in designing intelligent Web applications. Paul Meagher introduces Bayesian inference by discussing the basic mathematical concepts involved and demonstrating how to implement the underlying conditional probability calculations using PHP.

PHP / MySQL Scripts & Tools
Helpful php codes samples.

Serving XHTML with the correct mime type using PHP
Describes how to send XHTML with the correct mime type safely using PHP. Includes the ability to "fall back" to HTML if the viewing web-browser does not support XHTML.

Introduction to PHP Image Functions
An excellent overview of PHP image functions, including source code and interactive online examples.

Phptutorials.cjb.net
A free tutorials and advice on installing and using Apache, PHP and MySQL, primarily on Windows (WAMP).

PHP Common Mistakes and their Solutions
About the various security concerns and mistakes people make when developing, and their solutions.

Magic Quotes and Add Slashes in PHP
PHP Tutorial on magic quotes, why they are bad, and how to get around them.

PHP For Designers
PHP introduction for web designers by Matt Mullenweg.

PHP Feedback Form with Source Code
Tutorial for feedback, bug report, contact PHP forms includes all copy and paste code.

PHP and MySQL (Webmonkey)
Three-part tutorial covers installation, basic scripts, forms, and advanced topics.

PHP / MySQL Tutorial (Webmonkey)
Tutorial to make a dynamic site using PHP and MySQL.

Authenticate and Track Users with PHP (Webmonkey)
Learn how authentication, cookies, and sessions can add security and a personal touch to your site.

How to use SSI in PHP
Covers the basics on how to do virtual includes in a PHP file.