Rated 5 out of 5 stars
Working right on firefox 8.0a1 after manually editing FF maxversion into install.rdf file. Great extension.
@Frank E, in the ftp server it seems mozilla only publishes langpacks for namoroka, beta, aurora and nightly versions. For normal version it only publishes localized bundles. Look for folders with xxxx-l10n sufix here: ftp://ftp.mozilla.org/pub/firefox/tinderbox-builds/ , maybe in ../tinderbox-builds/xxxx-l10n/install