Actually i've been trying to install Phalcon on Ubuntu Server 14.10. To install php i've followed Phalcon's official documentation http://phalcon.io/en/download. After the installation i just did phpinfo() to see if the extension is activated or not.... But there was no phalcon extension on the page. Phalcon generated me phalcon.so in /usr/lib/php5/20121212 directory.
At the end of my $/etc/php5/apache2/php.ini file i've put 'extension=phalcon.so' which didn't work for me then i changed 'extension=phalcon.so' by 'extension=/usr/lib/php5/20121212/phalcon.so' which also didn't work.... Infos about my system : OS : Ubuntu Server 14.10 64bits PHP v5.5.12