r-e-l-i-e-f Rated 5 out of 5 stars

Have reinstalled this in FF3.6
Simple and effective.Yay!

It's not automatic... but here's how Rated 2 out of 5 stars

Given the absence of instructions in the extension or at developer's website, here's what to do:

1) Download & install, restart Firefox.
2) Open the drop-down menu of search engines
3) Scroll to the very bottom of the list, where you'll see the 'Manage Search Engines' menu. Select it. A control window should pop up.
4) You should see two buttons on the control window: A->Z and Z->A. Click on either.
5) The list should now be alphabetised.

This review is for a previous version of the add-on (1.0).