What is Kali Linux anyway?
Kali Linux is an advanced Penetration Testing and Security Auditing Linux distribution, and it is the new BackTrack. Yes!
Kali == The Latest BackTrack;
Why the new name?
Offensive Security, the company that sponsored BackTrack, speaks to have put in a lot more effort into this new Linux. They say that their plan for BackTrack-6 was so big that instead of trying to patch up the existing environment to conform to Debian policies and standards, it required new technologies and a new platform built up from scratch. Thus for the sake of these major changes they decided to call it a new name – KALI.
How is it Different?
Well, from an end user perspective, the most obvious change would be the switch to Debian and an FHS-compliant system, but for functionality details you might want to check the New Features included with KALI compared to its previous generation of BackTrack.
Here is a link to the FREE Download page. You can either download ISO for boot installation, or you can download a virtual-image that can run directly on your VMware (virtual machine).