VNC works very well for me. Check the wiki at
http://en.wikipedia.org/wiki/VNC

VNC is NOT a VPN client. VNC is a remote desktop technology.

Please do not get upset that some one gave the wrong answer. They are just
trying to help and it a simple misunderstanding. Please next time just play cool
and go on. Does that sound like a plan?

There is VPNC for Cisco's EasyVPN equipment in Synaptic. I do not use Virtual
Private Network and you may want to ask Ubuntu Forums for more information. I
all so came across this from Ubies wiki site.
https://wiki.ubuntu.com/Home?action=fullsearch&context=180&value=vpn&titlesearch\
=Titles

I using OpenVPN on Feisty right now to access my work network (Windows
2003 Server). Like Ubuntu, OpenVPN is open source. The web address is
http://openvpn.net/