check out the juxta project.
Do you perhaps mean http://www.jxta.org/?
If so, I think the OP wants a *client* rather than a generic networking infrastructure.
If you dump the whiteboard requirement, then any IRC server can be setup on your machine, firewalled to external ports, then setup an SSH server on your machine. SSH tunnelling can then be used by your friend to automatically connect to your server transparently via SSH. (depends on having decent SSH client + server; Putty on windows will do the client + tunnelling, not sure about a free windows server though).
Alternatively, just use MS netmeeting? It's bad, but if it works first time for you (which it often does), then it shoudl be fine - and it does have a whiteboard.