User Agent Switcher

I juz re-format my computer today and install Opera as my main browser. But then i feel like want to use Firefox. Later i install Firefox 3.0 to my computer. I install Firefox because i want to use its add-on, the User Agent Switcher.

Next, i want to download it from the main site of Mozilla addon page but i can't because they forbid me from downloading it. It really is a waste of time searching for an hour in google. I can't find it. Im using Mozilla Firefox 3.

UPDATE
OK.. i got the FireFox add-on. And i manually install them but unfortunately Firefox won't install it because it says 'no update'. HOHOH.... that really frustrating!!!!!!!! ARAGHHHHHHH!!!!!!!

I get it here
don't clicl the link of you want to download it. Right-click, and choose Save As.

See what happen when i install that Add-ons


After that is this: