Firefox 11 for Ubuntu
There is an official PPA that contains releases of Firefox from the beta channel: https://launchpad.net/~mozillateam/+archive/firefox-next.
If you want to install Firefox from this PPA, execute the following commands:
$ sudo add-apt-repository ppa:mozillateam/firefox-next $ sudo apt-get update && sudo apt-get install firefox
This tip is from here.