The iPhone was introduced at the Macworld Conference & Expo 2007 with a keynote address from San Francisco's Moscone West.

Wikipedia - Steve Jobs: http://en.wikipedia.org/wiki/Steve_Jobs

Steve Jobs - 2007 iPhone Presentation ( Part 2 of 2 ): http://www.youtube.com/watch?v=M0vTQm8Lkoo&feature=youtu.be