On the PHPHacks.com site today, there's a brief overview of some of the more popular PHP frameworks offered to date, including the Zend Framwork, CakePHP, and Symfony.
New frameworks are being released almost every other day in the PHP community. With over 40 frameworks available it's difficult to decide which framework works best for you, especially as each framework offers different functionality.
There's ten on their list, including the ones mentioned before and others like eZ Compontents, CodeIgniter, PHP on Trax, and the Seagull Framework. For each of them, they list out three to four bits of information about features/bundled modules/unique functionality/etc. It's some pretty good information, but I wish they'd also included one other thing for all of the frameworks - links to their homepages.