There are white-board programs that can do the same thing and more. They follow the T.126 protocol, so you could use them on linux and communicate with a group using windows Netmeeting3 for example. Irix's SGIforum, and the Suns X windows program SunForum and maybe others follow this protocol.
For a voice/video over IP program, try googling for 'GnomeMeeting'. From their website:
GnomeMeeting is an H.323 compatible videoconferencing and VOIP/IP-Telephony application that allows you to make audio and video calls to remote users with H.323 hardware or software (such as Microsoft Netmeeting)