I'm providing unofficial updates to the Cisco VPN client for Linux, because Cisco doesn't update their clients on a regular basis. Nearly all new kernel versions break the official Cisco VPN client and usually you should get working updates here.
Here’s the steps I took to get the Cisco VPN Client to work under Unbutu 7.04 (Feisty Fawn). In all reality, this should work with any version of Ubuntu, not just 7.04. I used this same method to get the Cisco VPN Client working on Ubuntu 8.04