John Jantsch has a great blog and business at Duct Tape Marketing. I was delighted when John asked me to do a podcast - here's what he said:

Bert wrote a fabulous and fascinating book on the subject called You've Got to Be Believed to Be Heard. This book sheds great light on how the human brain perceives the message you are communicating, whether it's one on one or to a group. One of my favorite quotes from the book is attributed to Emerson - "Who you are speaks so loudly, I cannot hear what you are saying."
Listen and learn about verbally presenting and speaking from someone who's been there.