Twitterfone launched in May to let Twitter users post new messages by calling in to a phone number and speaking out what they want to say. The service then converts the message to text and posts it to your Twitter account along with a link to the audio file. Here’s a test message I created at the launch. The service is a great way to leave a quick Twitter message when you’re away from your computer and only have access to a phone – the service offers local number in 19 countries and is expanding regularly. The company says 20,000 people have signed up for the service since launch.