One of the constraints of using SMS to evade state censorship in developing countries under repressive rule is literacy—or lack thereof. TwitterFone is a new service that converts voice to text and then posts it to Twitter. While Jott and Spinvox already enable voice to text conversion for Twitter and Facebook, TwitterFone is said to be far simpler to use.
According to TechCrunch,
The service launched moments ago into private beta. To use it you need to verify your phone number and Twitter account, and TwitterFone will then give you a local phone number to call to leave messages (they support the U.S., UK and Ireland now, adding more). Then, any message you send will be transcribed, and posted to Twitter along with a link to the recording. If the message is longer than 140 characters, just the first part is transcribed, but the entire recording is still available. There is a time limit of 15 seconds on the recording. The service is partially automated via voice recognition software, and flagged words go to a human for translation.