I meant to post about this on Wednesday when Imagick 2.0 was released but naturally forgot due to other distractions.
Earlier this week after several months in development Mikko and I have released a stable version of the ImageMagick extension for PHP, you can make use of all the useful features within ImageMagick without having to spawning a new process.
One of the largest benefits compared to the native image functions built into PHP via libgd is the support for over 100+ formats including PDF and MPEG if you want to extract a specific frame / page.
You can download the extension on PECL, it requires PHP 5.1.3 minimum and ImageMagick 6.2.4+.