I use the builtin VPN configuration of NetworkManager to connect to our Microsoft PPTP VPN server. It is a barebone VPN configuration tool(maybe i'm wrong) which routes all your traffic through the configured VPN. I'm rather looking for a sophisicated VPN client in Ubuntu Jaunty which is configurable and will be able to route traffic from certain sources or applications through the VPN and others through the default network. For example, our custom application traffic will go through VPN and others not.
Posted in superuser. As per suggestion, cross posting here.
Edit:
I was looking for a tool like KPNC recommended by Jure. But please post the steps to configure the traffic routing based on the application for your recommended tool if it's not so obivous. I went through the screenshots available in KVPNC and found it as very configurable but didn't found out how to configure what I want!!! Thanks.