Rated 4 out of 5 stars
The Translate Page function works great. But the "Translate This Selection" does not work for me - when I select the context menu item, nothing happens. I am running Firefox 8.0.1 on Windows 7 64bit.This review is for a previous version of the add-on (1.7.5).
Google Translate API.
As of December 1st, Google has disabled the old version of the Google Translate API and is now charging for the new version. http://code.google.com/apis/language/translate/v1/getting_started.html