LoRz

Change the settings in the system/config/email.php file.

$config['driver'] = 'smtp';
$config['options'] = array(
                            'hostname' => 'smtp.gmail.com', 
                            'username' => 'username@gmail.com', 
                            'password' => 'password',
                            'port' => '465', 
                            'encryption' => 'tls'
                        );

Sample code for sending an email.

$to = 'to@gmail.com';
$from    = 'from@gmail.com';
$subject = 'Suject';
$message = 'Message';
 
$swift = email::connect(); 
$message = new Swift_Message($subject, $message); 
$swift->send($message, $to, $from);

TCP_OUT for port 465 must also be enabled.