I know that this may not work for every situation, but I recently created an app for iPad that works as a simple teleprompter. I do a fair amount of corporate video for a small company, so this works great as we already had an iPad.
The app is free. Just search the iPad store for "On Air"
It's pretty basic but I plan to add functionality, like the ability to control speed with a "linked" iphone.
You can also visit the app's website here: http://www.ragusmedia.com/onair