1.Download firefox-5.0.1.tar.bz2 file.
2.Extract the File(just right click and select Extract here)
3. Move the folder to your Home folder(/home). Just cut and paste inside your home folder.
4.Open the Terminal and Enter this command(this will make your system recognize the new firefox location):
sudo ln -s ~/firefox/firefox /usr/local/bin/firefox
5.You also need to create a symbolic link from the system plugins folder, so the new version can detect the plugins. So enter the Following commandsin terminal
rm -fr ~/firefox/plugins
Next enter this:
sudo ln -s /usr/lib/mozilla/plugins ~/firefox/plugins
If you want to uninstall and like to work with default firefox:
Enter these commands:
rm -r ~/firefox
sudo rm /usr/local/bin/firefox