VSNotifications is a jailbreak utility which has been available for a few months. The tweak allows a jailbroken device running iOS 5 or higher to read out incoming notifications through a Siri-like voice synthesizer. With VSNotifications you can receive messages without even having to see the screen.
It's not hard to see how the tweak could be useful. When you're driving, VSNotifications is a great way to stay connected to your messages without breaking laws or endangering others on the road. The tweak could also make a jailbroken iPhone more useful to the visually impaired, or people who just like having their notifications read to them...