Scribblar - Scribblar is a free online collaboration tool that is perfect for online tutoring.
Empathy - Apps/Empathy - GNOME Wiki!
IDroo - A shared whiteboard for use by multiple Skype-users simultaneously. Features
Psi-IM - Psi-IM is a messaging program that is designed for the XMPP network.
OpenBoard - The OpenBoard software is an interactive white board software.
Gajim - Full featured and easy to use Jabber client