In a terminal type:
sudo apt-get install network-manager-vpnc network-manager-vpnc-gnome
After installing network-manager-vpnc and the gui (network-manager-vpnc-gnome) for xfce4 or gnome. Left click the NetworkManager panel icon and select VPN Connections>Configure VPN...
From there, import the network's VPN's settings file. After connecting you will be prompted for your password.