Backtrack or BlackUbuntu ?

I want to learn penetration testing, ethical hacking and other security based stuff..

1) Please tell me which OS is the best Black Ubuntu or BackTrack ?

2) I already have Windows 7 and Ubuntu 11.10 in my laptop. So is there any way to convert my latest ubuntu to backtrack /Black ubuntu? Else can i use Vmware to install blacktrack/black ubuntu on windows 7 ?

now i have installed backtrack 5 on virtual box in my windows 7 laptop.
But how access internet ?
My real os (windows 7) uses usb dongle to connect to internet.

Since it is not the same Question anymore, thread closed...
Open your new request in a new thread with appropriate title.
Thanks