Backtrack is such a linux distro (like ubuntu and fedora) specializing in computer/network security, BackTrack is
 the
 world’s
 leading
 penetration
 testing
 and
 information
 security
 auditing 
distribution.

With hundred 
of 
tools 
pre installed 
and 
configured
 to 
run 
out
 of
 the
 box,
 BackTrack
 4
 provides
 a
 solid
 Penetration
 testing
 platform
 
 ‐
 from
 Web
 application
 Hacking
 to 
RFID 
auditing
–
its 
all
 working 
in 
once 
place. Even backtrack is a separately linux distro all of application inside of backtrack can be run under ubutu or other linux distribution such fedora or redhat.
"How to run a backtrack application under ubuntu or other linux distro ?"
The guide bellow is the answer, follow the intructions bellow to add backtrack application/package in our database, so you can install or use it afterward.
  1. wget -q http://archive.offensive-security.com/backtrack.gpg -O- | sudo apt-key add -ok-
  2. sudo echo "deb http://archive.offensive-security.com pwnsauce main microverse macroverse restricted universe multiverse" > > /etc/apt/sources.list
  3. update package database by typing "apt-get update", wait until all proccess finish.
  4. open your synaptics, look "left side of your synaptics" 'you have backtrack application package now :)

if the list above can't work well, there is another instruction may help you : 
  1. echo deb http://repo.offensive-security.com/dist/bt4 binary/ >> /etc/apt/sources.list
  2. export http_proxy="http://myproxyserver.com:8080"
    wget http://repo.offensive-security.com/dist/bt4/binary/public-key && sudo apt-key add public-key && sudo aptitude update
  3. links -dump http://repo.offensive-security.com/dist/bt4/binary/ | awk '{print $3}' | grep -i deb | cut -d . -f 1 > backtrack.txt
  4. for i in $(cat backtrack.txt); do sudo aptitude -y install $i; done 

Here the are a list of backtrack application/package can  be used :
  •       BackTrack
‐
Enumeration

  •       BackTrack
‐
Tunneling

  •       BackTrack
‐
Bruteforce

  •       BackTrack
‐
Spoofing

  •       BackTrack
‐
Passwords

  •       BackTrack
‐
Wireless

  •       BackTrack
‐
Discovery

  •       BackTrack
‐
Cisco

  •       BackTrack
–
Web
Applications

  •       BackTrack
‐
Forensics

  •       BackTrack
‐
Fuzzers

  •       BackTrack
‐
Bluetooth

  •       BackTrack
‐
Misc

  •       BackTrack
‐
Sniffers

  •       BackTrack
‐
VOIP

  •       BackTrack
‐
Debuggers

  •       BackTrack
‐
Penetration

  •       BackTrack
‐
Database

  •       BackTrack
‐
RFID

  •       BackTrack
–
Python

  •       BackTrack
–
Drivers




,