Manoj Sachwani has put together a summary listing of some of the popular PHP frameworks available today along with a brief summary of each.

Recently, I took on a project to code a web application from scratch. [...] Now, Most of you would suggest I should use a pre-existing open source solution, and logic would dictate I should probably use one. Sure! I should...But, How then am I going to learn and become more geeky and at the same time save time develop and deliver the web app? Enter, PHP Frameworks.

Some of the frameworks that made his list include Akelos, CodeIgniter, Prado, the Zend Framework and Symfony.