TwitterBar

Allows you to post to Twitter from Firefox's address bar. A small Twitter icon sits to the right of your address bar; clicking on it will post your tweet, and you can hover your mouse over it to see how many characters you have left.

You can also post by typing "--post" at the end of your tweet. Clicking the Twitter icon when visiting a webpage will send a tweet containing the URL of the webpage you are currently viewing.

As of version 2.9, you can post to multiple Twitter accounts. To post to a specific account, just type --@account_name at the end of your tweet (but before typing --post). e.g., "Tweeting from my personal account. --@jimmy2424 --post". (If you have authorized more than one account but don't specify which one to post to, you'll be asked to select from a list.)

To add a new account, just type --account in the URL bar. You'll be prompted to sign into Twitter with the new account.

You can manage your accounts from the options dialog. Just type --options in the URL bar.