Making money off an iPhone app requires at least one person to create it and at least one person (can be the same) to tell the world it exists. If your goal is to make money off an iPhone app as I understand it, you should first see what's involved with each role. Find out what tools developers use and how to use them, and try learning iOS development. Do Google searches on iPhone app marketing and get a very basic idea for what that entails.
If you're starting from scratch, it will be a lot of work. See how far you get after a week or two of research and tinkering around with development, and make sure it's something you really want to do.
I personally used the Unity engine to develop my first released game by myself. Only took me about 60 hours total as I tried to keep it as simple as possible. It did poorly in the app store but I still made enough sales to recover development costs at least.