TweetDeck in #280Characters
Twitter has released 280-character tweeting, but only to a small group of people during a trial period. This Chrome extension
adds once added the ability for everyone to tweet in 280 characters on TweetDeck and Twitter.com.
The source code is available here on GitHub and pull requests are invited.
Update Sep 28: The party is over at twitter.com, which now appears to be validating tweet length at the server, so this extension no longer enables 280-character tweets there. But it still works at tweetdeck.twitter.com!
Update Oct 5: This extension no longer works. Twitter and TweetDeck are now both validating tweet length at the API.