This article says $21 million was spent on iphone applications the first month the iphone was released, with Jobs predicting it will be a $500 million to $1 billion market: <a href="http://gigaom.com/2008/08/10/iphone-app-downloads-are-up-what-about-their-usage/" target="_blank">http://gigaom.com/2008/08/10/iphone-app-downloads-are-up-what-about-their-usage/</a>