From this site, you can sign up for the developer program and download the necessary tools required to build iPhone apps. There is a developer fee of $99/annually in order to submit your newly built creations to have them appear on the app store, but you can download the tools and play around with them with a free account.
iPhone Dev SDK is a community for software developers interested in the iPhone SDK platform. Founded in March 2008, iPhone Dev SDK was one of the first communities for this revolutionary new platform.
What separates iPhone Dev SDK from the others is the friendly atmosphere the community provides for developers of all abilities. Whether you’ve been programming your entire life or are just now getting interested, you’ll find yourself welcomed to the community.
iCodeBlog.com features some of the best tutorials on the web, both on beginning and more advanced development concepts. It should get the novice beginner off to a good start as well as teach the established user a few things about parts of the API that they may have not explored yet. The blog is updated on a regular basis and would make a great addition to any iPhone developer’s bookmarks.
Go through this site to earn more money with free apps with ad integration .
useful one for tracking your application sales and graph .