Banner free is a nice little application that turns your iPhone into a portable sign board.
It allows the owner to set a customizable message that will scroll right to left when holding the iPhone in landscape mode.  

Features I’d like to have: change the colour of the scrolling text and the background, the speed and direction  of text scrolling, and some cool blink effects as well (bring back the <blink>)

I’ve had it on my phone for several months but have not found it a needed application.. still I keep hoping that the occasion will arise so the app stays on my phone.