There are a lot of great iPhone Photo Apps to choose from. A simple search under "photo" in the App Store came back with a search result of 2199 and "camera" shows 2197.
I count twenty-one on my iPhone/iPad right now! Ryan probably has a dozen more. The more you use the apps the more fun there is to have. The creativity and uniqueness come in the layering use of many apps on one photo.
To see samples of photos and a to get a link to a free copy of David Molnar's book visit the Parachute Media Blog post where this was originally posted.