how to install two firefoxs in ubuntu 11.04

Firefox 5 is out now. My ubuntu has updated Firefox Browser to 5, and it works fine, and I do feel it's faster, but the problem is that some add-ons does not work in the new Firefox. If this is a case for you too, or you just like to have old Firefox in your machine, here is how I did it. 1. Go to Mozilla Old download page at http://www.mozilla.com/en-US/firefox/all-older.html, and pick one and download it. 2. Unzip the file and save it to somewhere, says, /home/adam/firefox. 3. Close the existing firefox, and at your command line, change directory to firefox folder, and then enter the following command

./firefox &

Note that you have close exiting Firefox, otherwise, it will trigger the Firefox 5 not Firefox 3. And you can click the file named firefox to open it, but you have to select RUN, not open it in the text editor.