If you have been using Linux for a while then you have come across packages you love using, but are not in the Ubuntu repositories. Some packages have there own repositories. These have to be added to the sources.list file of apt.
This new article on Bright Hub explains how to do this. It is written for the “point and click” people who want to use Adept or Synaptic. Even though the Terminal way is described as well, it is more geared to the n00bs and beginners.
For more please click the link below.