ClearType is the perfect application for people who find it difficult to type on their iPhone while walking. ClearType displays a live stream from your camera while allowing you to type over the top of it. Once you have finished typing, you can then output the text to an App of your choice.
App's that are supported:
ClearType also comes with a basic translucent web browser, so that you can do some internet browsing while still be able to see where you are going.
ClearType is a must have App if you want to make using your iPhone much easier.
Please note a camera is needed to run ClearType, therefore this excludes iPod Touch's and iPad's.