Mozilla Firefox 4.0 Beta 3 Pre has been released.If you want to test the latest Mozilla Firefox beta release in Ubuntu,you can add ubuntu-mozilla-daily ppa into your repository.It should add the latest packages as quickly as possible.
Open up a terminal window from Applications->Accessories menu and run this command to add the PPA:
sudo add-apt-repository ppa:ubuntu-mozilla-daily/ppa
update your system and uset apt-get install command to install the packages:
sudo apt-get update sudo apt-get install firefox-4.0
Once installation finish,you see “Mozilla Developer Preview Web Browser” in Applications->Internet menu.
