I’m now providing an updated Linux Penetration Testing Laptop Setup document to help install popular and useful vulnerability assessment tools for the Linux operating system. You can go and obtain Backtrack but I feel that you will have more understanding of the tools and Linux in general if you install the tools yourself. You will also have the most current version available. See Configuration Tutorials for the latest document.
Update: The latest version is now v4 on Ubuntu 11.4 Natty Narhwal.