BackTrack - is a SLAX based linux distribution derived from merging two penetration testing distributions, Whax and Auditor. BackTrack features user modularity: the user can customise the distribution to include personal scripts, or additional tools.
OWASP LiveCD 2008 - similar to BackTrack but focused on web applications
Damn Vulnerable Linux (DVL) - is a Linux-based tool for IT-Security; is a perverted Linux distribution made to be as insecure as possible. It is collection of IT-Security tools. Additional it includes a fullscaled lesson based environment for Attack & Defense on/for IT systems for self-study or teaching activities during university lectures. It's a Live Linux Distro, which means it runs from a bootable CD in memory without changing the native operating system of the host computer. As well it can be run within virtual machine environments, such as qemu or vmware. There is no need to install a virtual machine if you use the embedded option. Its sole purpose in life is to put as many security tools at your disposal with as much training options as it can. It contains a huge ammount of lessons including lesson description - and solutions if the level has been solved by a community member at crackmes.de.
Samurai Web Testing Framework - is a live linux environment that has been pre-configured to function as a web pen-testing environment. The CD contains the best of the open source and free tools that focus on testing and attacking websites. In developing this environment, we have based our tool selection on the tools we use in our security practice. We have included the tools used in all four steps of a web pen-test.
(para os links --> Google)