Ubuntu source generator allows you to generate a custom sources.list file for your Ubuntu software sources. This will give you a customized software source list which includes all the required packages for applications you use frequently. It will also let you install many packages you could not install earlier because you did not find them in the package-manager. This file(sources.list) is used by the package manager for its updates and managing the list of Applications in the Software Center in Ubuntu 9.10.
To generate the sources.list visit the Ubuntu Sources List Generator homepage. This is a PHP application and is very comprehensive.
There are options to select the application as well as the source, separately. Sources for third party applications like Skype, Opera and Vuze can also be added. This gives us a complete sources.lst file. On hitting the generate button, the application provides us with the sources.lst file and the GPG keys, which need to be added manually.
Save the text provided as a sources.list file and replace the file at /etc/apt/sources.list with the new file.
Add the GPG keys and then update your packages at synaptics package manager. You should have new packages and applications in your package manager as well as in the Software Center after reloading the package list.