I\'ve read quite a lot answers but couldn\'t figure out why xdebug doesn\'t work.
php.ini:
[xdebug]
zend_extension=\"/usr/lib/php5/20090626/xdebug.s
Since this seems to bother more and more people trying to install xdebug via pecl here are the options:
sudo apt-get install php5-xdebug
Using PECL to install X-Debug for PHP5.5 as @Slayer Birden also answered will not work up to now and I don't think it will change in the near future.