The below instructions will show you how you can install all of the Backtrack applications on your current Ubuntu installation.
Add the following line to your /etc/apt/sources.list
deb http://repo.offensive-security.com/dist/bt4 binary/
Now to import the Backtrack GPG key and to update the sources:
[email protected]:~$wget http://repo.offensive-security.com/dist/bt4/binary/public-key && sudo apt-key add public-key && sudo apt-get update
Fantastic! Now we have all the new Backtrack applications ready to install. You can find these applications in your Synaptic Package Manager