Yesterday came the Firefox browser version 4 with many improvements in speed, standards support and interface. If you want to install Ubuntu 4.10 or Ubuntu 10.10 just add the repository and install.
From a terminal (CTRL + ALT + T), run the following commands:

sudo add-apt-repository ppa:mozillateam/firefox-stable
sudo apt-get update && sudo apt-get install firefox ubufox

Then we install the language packs to systems 32-bit systems or 64-bit .

In gnome the look of Firefox 4 is not exactly like that of other systems. For example we have the menu bar. The extension Movable Firefox Button can give a more like moving the bar to a button at the top left.