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.