title: Available & Most Profitable Ad System for iPhone App?
body: <p>After release my first iPhone application I had a fairly decent turnover in turns of sales considering it was a pretty niche application in the health and fitness category.  However, I decided to make the application free until the next update and in the first 3 days downloads of my app have increased by 1433% - which is quite staggering.</p>
  
  <p>So it got me thinking maybe the option of a free application, with ads would be a better option.  With that said, what are the available options for integrating ads into an iPhone app and which is the most profitable?</p>