Ken Seto of Endloop wrote this in-depth report of how they built and launched iMockups and made $100k from it. There are some good bits if you're looking to make money from iOS apps, like:
by keeping our app at $9.99, we are able to do well with less sales. Because it's a niche app for professionals, we think the price is not as much of a barrier. With a higher price point, just a single app sale in every country will result in a decent take for one day.
the 30 second video I uploaded to YouTube got over 50K views within the first week. I sent the press a very short email containing a link to the video, highlight that it was only 30 seconds.