True to form, Steve Jobs delivers the iPhone (the bottom QuickTime link focusses on the launch) to the public in an examplary way. Whether or not you give a proverbial about the technology, watch this from a presentation style point of view. His visuals always support what he says, never the other way round. He constantly repeats and summarises so the key information comes across clearly. He's well rehearsed. He uses humour appropriately.
If you like this, get to Presentation Zen sharpish.