Firefox is the default web browser for ubuntu. Even though you can find firefox preinstalled when you installed any version of ubuntu. With ubuntu 10.04 and ubuntu 10.10 the version 3.6 will be installed in your computer. Since the firefox 4 is still in beta version and will be schedule to be release in 2011 many ubuntu user want to install firefox 4. You can’t install firefox 4 from the ubuntu software center. If you type firefox 4 in ubuntu software center the result will be blank. Therefore you have to install firefox 4 from the terminal.
To begin installation Open terminal and run the following command
sudo add-apt-repository ppa:ubuntu-mozilla-daily/ppa
sudo apt-get update
sudo apt-get install firefox-4.0
After running the following code the firefox 4 will be instaled in the computer. To view firefox 4 go to Application>>> Internet>>Minefield 4.0 web browser.
Screen Shot of Firefox 4 in ubuntu