For some odd reason I did not understand why imagick 2.3.0 did not want to install with ImageMagick 6.8.9-7. Apparently the directory structure changed in the last versions of ImageMagick.
The solution is pretty simple:
ln -s /usr/local/include/ImageMagick-6 /usr/local/include/ImageMagick
After this just follow the next steps and you’re in business:
pecl install imagick-2.3.0.tgz
I’m running PHP 5.3.28, however keep in mind that this particular version of imagick (2.3.0) won’t work in PHP 5.4 and higher.