What is Tweetmic?
TweetMic is a simple and intuitive Twitter client app for the iPhone that allows you to make high-quality audio recordings or "Tweetcasts" and publish them directly to Twitter. There is no limit to how much you can record and you don't need to sign up for any additional service to start using TweetMic.
(Thanks to Todd Little for the tip).
What would or should you tweet? The same kind of stuff you tweet now. Or how about an interview highlight or a promo for stuff upcoming or a hook montage or a backstage tidbit, etc.
We are, after all, a primarily audio medium. Building that capability into Twitter makes it even more a natural extension of radio.