I released TwitterScript v3 today. This one is a lot more improved in its functionality. If you are a Twitter-addict to install it with Greasemonkey. This release fixes one of its worst shortcomings: sending username and password for every Firefox session.
Thanks to @aditya who tickled me to work on it, TwitterScript now stores the username and password and lets you send tweets without having to type the username and password everytime you fire up Firefox. But that could be a problem for those who are using shared computer. I suggest them to use the last release which you can install from here.
For this new TwitterScript, install it from Userscripts.org. If you are installing TwitterScript for the first time, I suggest you to uninstall it by going to Tools » Greasemonkey » Manage User scripts... TwitterScript and clicking uninstall.
Then install TwitterScript. Now, you have to set the username and password. Hit SHIFT+ALT+T (as usual) and type in your username and password in the following format: [your username]:[your password] The format must be like this. Then click "Tweet!" Now you can send Tweets!
If you find some problems/bugs with it, do let me know! :)