After the Safarify bookmarklet http://tr.im/Go3g, there now is one for a Firefox as well – Foxify: http://tr.im/Go3f
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
After the Safarify bookmarklet http://tr.im/Go3g, there now is one for a Firefox as well – Foxify: http://tr.im/Go3f