A great overview on public speaking from http://isites.harvard.edu/fs/html/icb.topic58703/winston1.html gives a overview on public speaking. Here’s the summary from the site.
In this skillful lecture, Professor Patrick Winston of the Massachusetts Institute of Technology offers tips on how to give an effective talk, cleverly illustrating his suggestions by using them himself. He emphasizes how to start a lecture, cycling in on the material, using verbal punctuation to indicate transitions, describing “near misses” that strengthen the intended concept, and asking questions. He also talks about using the blackboard, overhead projections, props, and “how to stop.”
Running time: 45 minutes.