Post to Twitter from the Firefox address bar : TwitterBar

Twitter is the micro-blogging site that is getting ever more popular. With posts limited to 140 characters the emphasis is on quick and easy. TwitterBar is a twitter FireFox extension which lets you tweet directly from the FireFox 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.

See Also: 52 cool Twitter Plugins for WordPress

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.