Time to jam around with the code, since an essential part of becoming familiar with any platform is building up a wealth of experience of what is possible, what is worth repeating and what doesn't work at all.
Try changing the appearance of the app in more fundamental ways than simple changes of color (critical though that can be). Is there something you can do to make those labels more engaging? Can you fit the app's appearance to some (possibly invented) corporate image? Could the layout be improved?
Can we add a button to the launch screen that will disable the auto-advance feature? We'd need to store that preference too.
How would the user experience improve if we added a little animation magic to the transition from the launch screen's starting UI and its prompting UI? Any other candidates for animation?
If you already have more than rudimentary experience with developing for the iPhone, you might wish to add the ability to store and recall multiple Prompt...