Free Content Management Systems (CMS) using PHP Scripts

Expression Engine Core
The Core version of this software is free for personal sites. It is a fully featured content management system and blogging software that has one of the easiest to understand and modify template system (for your site design and theme) I've come across. It is versatile, has a sophisticated user/user-group system (for managing your users), easy to setup and get started, highly configurable, etc. It uses MySQL for its database. You may also want to read WordPress Vs Drupal Vs Expression Engine: Which Blog Software Should I Use?
This is an open source content management system that purports to be search engine friendly, in that it has a site map (using the site map protocol?) generator and automatically creates search engine friendly URLs. It allows you to manage multiple websites from a single installation, has built-in caching to reduce the number of database queries (otherwise you may exceed your web host's resource limit), has a template and style sheet system so that you can customise your site, and is able to share its user database with 3rd party applications like certain forum software so that your users only need to register once for your site. The software is released under the GNU General Public License.
Drupal is an open source content management system (CMS) or platform that uses PHP and MySQL. It allows an individual user or even a community of users to publish, manage and maintain your website. You can use it to create blogs, forums, picture galleries, file upload and download sites, forums, collaborative authoring environments, podcasting, peer-to-peer networking sites, etc. The system is modular and highly customizable. It is licensed under the GNU General Public License. You may also want to read WordPress Vs Drupal Vs Expression Engine: Which Blog Software Should I Use? If you are looking for tutorials, see How to Setup the Drupal Content Management System and its follow-up How to Set Up a Blog with Drupal.
TextPattern Content Management System
TextPattern is an open source CMS that attempts to make it easier for the average user to modify its templates. Its templates use a simple syntax known as Textile that allow you to use a few simple markers to indicate things like images, hyperlinks, etc. The software allows multiple contributors, supports plugins, etc. TextPattern uses PHP and MySQL.
Drake CMS
Drake CMS is a PHP-based open source content management system that does not need any database system to be installed, although it supports a number of them (including MySQL, PostgreSQL, SQLite, Sybase, Frontbase, MaxDB, MS SQL, etc) if you have them. You can use it to create community-based portals, magazines and newspapers, simple personal or family websites, company or organisation websites, etc. It has a hierarchy of users, starting with the Admistrator down to the simple website visitor, with the facility to control the access rights of each of these user levels. You can create subsites with this CMS without replicating the CMS files.
Joomla! Content Management
Joomla! is an open source content management system (CMS) that can be used to power your website and allow you to easily manage it from an online interface. It includes an integrated WYSIWYG editor, support for multiple users/editors, a simple poll engine, several templates, etc. You can augment the features provided by the basic CMS installation by adding their extensions. Extensions available include blogging software, calendars, directory services, email newsletters, e-commerce and shopping cart engines, image and multimedia galleries, forums and chat software, banner advertising systems, business and organizational directories, dynamic form builders, etc. Joomla! requires that your web server be running Apache and has PHP and MySQL installed.
OpenCMS is an open source website content management system (CMS) that uses Java, JSP, XML, MySQL on Tomcat (a Java Servlet container and web server). It comes with an integrated WYSIWYG editor and a simple text editor for Internet Explorer and Mozilla-based browsers like Firefox. The CMS software allows you to view your workspace in an Explorer-like window, edit files by changing specific elements within the page or directly editing them using the built-in WYSIWYG editor, etc. This program is licensed under the GNU General Public License.
PHP-Fusion is a content management system (CMS) that uses a MySQL database to store the contents of your website. It requires PHP 4 running on an Apache server. The program is released under the GNU General Public License.
CMSimple Content Management
CMSimple Content Management is designed for webmasters with relatively small sites (less than 2 Mb in text content). It does not need your site to have a database - the content of your site is stored in a single HTML file. It has an online JavaScript-based WYSIWYG editor that works in Mozilla and IE 5.5 and above (doesn't work in other browsers). The program is free, but requires you to preserve the link to their site.
phpwcms - Web Content Management System
phpwcms is a content management system that uses PHP and MySQL. It includes multiple WYSIWYG editors, a frontend CSS editor, image resizing capabilities, file manager, support for meta tags, template editor, W3C conforming frontend rendering, etc. It can be installed on Windows 2000/XP, Mac OSX and Linux. The package is released under the GNU General Public License.
TYPO3 Open Source Content Management System
TYPO3 is an open source content management system that is multilingual; allows WYSIWYG editing using a rich text editor (this feature is only for IE Windows users); has wizards for making tables, bullet lists, mail forms, etc; allows multiple page editing; allows offline editing, preview of content online, scheduled publishing; has an indexed search engine, a direct mail or newsletter system, etc. Administrators have access control (the ability to control access to various parts of the system), statistics, logging, version control with unlimited undos, raw database access, etc. You can use HTML templates, PHP scripts, create protected areas, and so on. The entire system is released under the GNU General Public License.
BIGACE Web CMS: Content Management with Smarty Templates
The BIGACE CMS supports multiple websites on a single installation, template support, autogenerated menus, content hierarchy with unlimited depth and size, a category system, workflows, online WYSYIWYG editor, full-text search (including the name, description, catchwords as well as the content), integrated statistics, search engine friendly URLs, etc.
ezContents Content Management System
ezContents is an open source website countent management system that uses PHP and MySQL. You can add authors that write content, manage permissions, workflow, create a layout, etc. It supports both sites with frames and those without.
phpCMS - PHP Content Management System
This PHP content management script includes a file manager, full text search engine, online editor, statistics, dynamic menus, etc. Unlike many of the other content management systems (CMS), this one works with flat files.
This content management system is template driven and has a search engine, dynamic navigation bar, article posting, banner management, news posting, link indexing, etc. It is released under the GNU GPL. Note that development of this CMS has stopped, and at this time, the site is encouraging users to migrate to another CMS.


Your Title