phpLiveChat
phpLiveChat allows you to chat LIVE one-on-one with your customers via your website. Instantly notifies you when someone wants to chat, notifies you when a user leaves chat session, and online/offline images change on the fly. It can handle multiple support chat requests at one time, or forward chat sessions to other representatives, online sound events, initiate Chats, Track Visitors (notify you when they browse, or leave the site), push webpages, multiple departments, deptartment-specific ICONS, page multiple departments, and more. Written entirely in PHP and Javascript.