Has anyone found an ipsec client for the n80 yet?
Ipsec client
The Nokia Mobile VPN is, but the problem is in getting it configured. If you check the Forum Nokia ( http://forum.nokia.com/ ) discussion boards and search for discussion threads with "VPN" in the title, and pick the one with most replies, you'll see.
No other VPN clients are available by anyone else for S60 3rd Edition based devices, as far as I'm aware.