A Netscape.cfg/Autoconfig file which loads settings from Group policy
This project is mostly based on GPOFirefox by Marco Di Feo (http://marco-difeo.de/gpofirefox/) His project also includes a GP ADM file available at http://sourceforge.net/projects/gpofirefox/files/
The main difference between this project and GPOFirefox is that some settings while can be changed by an extension, aren't used that late in the Firefox start-up process (for example, browser.useragent.locale) that's where Autoconfig files come in which are executed earlier.
Simply place mozilla-gp.cfg in the install directory of Mozilla Firefox, and copy local-settings.js in the defaults/pref folder. After restaring Firefox, your group policy settings should be automatically picked up.