One of the most frequent questions I get on presentations and other talks is, "What should I do with my hands?"
The simple answer is: Do what comes naturally. Use your hands as you would in conversation, though adapted to your environment.
This question, like many others, comes from people thinking about what they will do when it's time to get into "presentation mode." This makes them self-conscious and distracted.
Please select this link to read the complete blog post from John Millen.