Finding Out What Php Mods Are Installed

[krAnk]

Is there a way to find out what modules are installed for php? I'm in a need of ImageMagick or NetPBM being installed. If they are installed, how can I obtain the path to these mods?

[QuickGold]

ImageMagick is installed and the path is: /usr/bin

[eugene]

Create a php file with the following contents:
<?php
phpinfo();
?>