Hi cet, PPA are simply another set of repositories you can configure into your /etc/apt/sources.list file. Then click on reload with Synaptic Package Manager or with the user level command issue: $ sudo apt-get update prior to issuing the install command for firefox: $ sudo apt-get install firefox; or use Synaptic Package Manager to do it. See: Install Firefox 4 In Ubuntu 10.04 / 10.10 Via PPA Repository - The Proper Way for details. -- Tom