https://www.torproject.org/torbutton/
The prjoject could not keep up with the frequent changes in FF. After having used it I found out that it was not practical anyway to have tor activated all the time so I only set it up in one Browser that became my "Safe surf Browser".
Now this is exactly the way the Tor project is going!
They have made a browser bundle where everything is set up for you and works out of the box!
If the tor-browser-en is not in your repo then you can download it from the project page
This gives you a FireFox with Vidalia and a working Tor. It does not disturb your current Firefox installation and they work fine side by side.
So to surf safely you can now hit <ALT> + <F2> and enter tor-browser-en
Flash and java will be deactivated but you can click the area and activate it temporarily from there. It is not to bad on speed either.