Most people are terrified of public speaking. I personally can do it, but I tend to talk to fast and use way to many “ummms”. There aren't a lot of good books out there to teach you better public speaking, but Confessions of a Public Speaker is a book you should definitely read if you have any public speaking in your future.
The author of Confessions of a Public Speaker is Scott Berkun. He is a former Microsoft executive who now is a writer and professional speaker. I love that this book is written at a level that anyone can understand. I also like that the advice he gives can be used for any sort of presentation you will have to do. There are plenty of real world examples, and lot of usable do's and don'ts. Berkun suggests that presenters first consider the needs of the audience — Who are they? What are they interested in? What do they want to learn? How are you going to keep them entertained? You would be amazed at how many presenters don't take any of these questions into consideration and their presentations will show that. One of the most important tips that he teaches is to keep your audience entertained and they'll forgive all kinds of other mistakes. I also have to agree that you need to keep your speech in ten minute chunks due to attention spans. I also recommend that you read the entire book including the very last page and the back of that page. Trust me on that.
Confessions of a Public Speaker is a must read for all public speakers. It's also a great read even if you aren't. It's a quick funny read, and you'll walk away with a lot of really great knowledge.