install the new Firefox 6 without losing your old version? Actually, it’s very easy, but it’s not as easy as in Windows.
1. Go to Firefox Beta download page.
2. Download, and make sure that your file is not corrupted.
3. Extract the source file.
$tar xvf firefox-6.tar.bz2
4. Copy to lib directory
$sudo cp -r firefox /usr/lib/firefox-6
5. Create a link to the executable file
$sudo ln -s /usr/lib/firefox-6/firefox /usr/bin/firefox-6
6. Create a link once again
$sudo ln -s /usr/bin/firefox-6 /usr/bin/firefox6
Ok, the Firefox 6 has been installed on your Ubuntu.
Now, the last step is create a app launcher on your Desktop.
Right click on the Desktop->Create Launcher