Apostle provides a nifty facility for sending app-generated, transactional emails from your application including Wordpress-like mail formatting and full tracking (delivery, opening, clicking etc.) of all emails sent. No need to set up email facilities on your app server!
The basic idea is to create a complete mail message and store it a Db table along with all info necessary for sending valid emails (to_email, from_email, from_name, subject etc.)
require_once 'Mail.php'; // PEAR Mail require_once 'Mail/mime.php'; // PEAR Mail_mime require_once 'Mail/Queue.php'; // PEAR Mail_queue require_once 'Mail/Queue/Container/mdb2.php'; // PEAR Mail_queue mdb2