How-To: Add a Debian Repository
Debian and Debian based distributions (Linspire, Xandros, Ubuntu, and Mepis to name a few) use a tool called APT (Advanced Packaging Tool) to manage all software on the system. The term "package" refers to an individual file with a .deb extension that contains either all or part of an application.
APT checks to ensure that all necessary packages are available prior to installing a program and also prevents the accidental deletion of a package if another program is dependent upon it. All available software is stored in a repository. Most of these are online, but one could just as easily be contained on a CD-ROM or DVD.
Your distribution comes with some default repositories that are already setup, but these contain only a portion of the freely available software out there waiting for you. The following guide explains how to add additional repositories to your sources list so you can expand beyond the software limits set by your distribution.
Warning: Some distributions such as Ubuntu are not fully compatible with standard Debian packages. Please consult your distribution's documentation for find out what is considered safe.
The /etc/apt/sources.list file contains the details for each available software repository. This file can either be edited manually or it can be modified by using a graphical manager. Examples for both are provided below. All entries in the sources.list file follow a format with 4 distinct regions: package type, web address (URL), distribution, and section(s). One or more sections can be included.
deb http://host/debian distribution section1 section2 section3 deb-src http://host/debian distribution section1 section2 section3 deb http://http.us.debian.org/debian stable main contrib non-free deb-src http://http.us.debian.org/debian stable main
Select Settings -> Repositories
Select New and enter the information into the fields as shown.
Once the fields have been filled select OK to save and return to the main screen. Click Reload to update the package lists and you are now ready to install software from your new repository.
Additional ResourcesDebian APT HowTo