GnackTrack is a Live (and installable) Linux distribution designed for Penetration Testing and is based on Ubuntu. Although this sounds like BackTrack, it is most certainly not; it's very similar but based on the much loved GNOME!
MirrorCode:http://www.gnacktrack.co.uk/downloads/GnackTrackR3.iso
Code:http://www.webweenievideos.com/downloads/gnacktrackr3iso.php