Steve Jobs of Apple is considered a great presenter. Here are some excellent advices and tricks [video + slides] for delivering an effective presentation from Businessweek columnist Carmine Gallo, who is also the author of the book - The Presentation Secrets of Steve Jobs (via Digital Inspirations).
"Your time is limited so don't waste it living someone else's life. Don't be trapped by dogma - which is living with the result of other people's thinking. Don't let the noise of others' opinion drown out your inner voice. Stay Hungry, stay foolish." - Steve Jobs