TwitterFox

Firefox extension for Twitter

TwitterFox is a Firefox extension that notifies you of your friends' tweets of Twitter. (former name is TwitterNotifier)

This extension adds a tiny icon on the status bar that notifies you when your friends update their tweets. Also it has a small text input field to update your tweets.
New feature of Version 1.5.4.1 ¶

* Support Firefox 3.0b3, b4, b5, and nightly build (beta)
o There are some problems with Firefox beta 4 on Windows or earlier platform. Check FAQ/Known issues.
* Support es-ES, nl-NL, zh-CN, zh-TW, fr-FR, and nb-NO locales
* Make contrast on timeline
* Sound notification
* Save state (entered text, received timeline id)
* Tab key navigation
* Fix bugs

Complete change logs of TwitterFox