Convert current Messaging system to a live chat

I have a social network with a simple messaging system written in php on the Zend Framework that connects to a MySQL database. I need the current system and code converted to a live messaging system like Facebook, where chat is instant and integrated into the theme and current layout (buttons, links, etc.). The new chat should have a popup bar, similar to that of Facebook, that shows online friends/users and be integrated into the current messaging page, with a notification for the two parties chatting that the other person is typing a message, and when sent, is showed instantly to the other person without having to reload the page. Please provide a link to similar work when bidding.