Which Chat system to use

Hi, I need to add a simple chat system to my site and I am trying to find out good solutions, free or paid. Some of the requirements : - php :) - uses some sort of template system (smarty better) - support for private chats - source code available - one chat room (except for private chats everybody sees everything) So far the chat systems I've found are too complex (need to register the nick before entering the chat, confusing interface), not stable enough ( http://www.phpfreechat.net/) or integrated with other systems. There is no need for : - multiple chat rooms - operator/ban - registration of the nickname - archive of previous chats thanks.