Twtio Audio Recording HD
Twtio lets you post audio on Twitter from your iPhone 4 or 3GS. Its super easy to use.
Heres how it works:
1. Login Using your twitter account
2. Record an audio
3. Insert a tweet
4. Post it on Twitter
A link to your audio, along with your message, will automatically be posted to your Twitter account. Pretty simple and easy, eh?