The iPhone 4 is a smartphone that was designed and marketed by Apple Inc. Following a number of notable leaks, the iPhone 4 was first unveiled on June 7, 2010, at Apple's Worldwide Developers Conference in San Francisco, and was released on June 24, 2010, in the United States, United Kingdom, France, Germany and Japan. It is the 4th generation of iPhone, succeeding the iPhone 3GS and preceding the very similar iPhone 4S. More: en.wikipedia.org.