Ajax chat, auto update.
Display as IPS widgets, so you can place it in sidebar or top page.
Sound notification. User can toggle on/off.
Block users.
Announcement (on Top or Tab).
Support emoticons.
Flood control.
Permissions for viewing, chatting & management.
Pictures :
Code:
http://community.invisionpower.com/files/file/7465-bim40-chatbox/