CodeIgniter: an open source Web Application Framework that helps you write PHP programs.
Yii is a high-performance component-based PHP framework best for Web 2.0 development.
CakePHP is a rapid development framework for PHP that provides an extensible architecture for developing, maintaining, and deploying applications. Using commonly known design patterns like MVC and ORM within the convention over configuration paradigm, CakePHP reduces development costs and helps developers write less code.
The Akelos PHP Framework is a web application development platform based on the MVC (Model View Controller) design pattern.
a Highly modular plugin based Code Management System and Framework. PHPDevShell can offer you immediate general used functionality with a user interface for your next proje.
Symfony is a full-stack framework, a library of cohesive classes written in PHP.
Extending the art & spirit of PHP, Zend Framework is based on simplicity, object-oriented best practices, corporate friendly licensing, and a rigorously tested agile codebase.
A bottom-up rewrite of the PHP scripting engine. It features a modular architecture, vastly improved performance, and greater scalability.
QPHP is an event-driven(EDP), component-based web framework similar as architecture to ASP.NET