In BusinessWeek online, an article on how Steve Jobs makes dynamic presentations :

Practice, Practice, and Practice Some More
Jobs takes nothing for granted during product launches. He reviews and rehearses his material. According to a Business Week article on February 6, 2006, "Jobs unveils Apple's latest products as if he were a particularly hip and plugged-in friend showing off inventions in your living room. Truth is, the sense of informality comes only after grueling hours of practice." The article goes on to say that it's not unusual for Jobs to prepare for four hours as he reviews every slide and demonstration (see BW, 2/6/06, "Steve Jobs' Magic Kingdom").

Keep It Visual
Speaking of slides, there are very few bullet points in a Jobs presentation. Each slide is highly visual. If he's discussing the new chip inside a computer, a slide in the background will show a colorful image of the chip itself alongside the product. That's it. Simple and visual.