I recommend Richard Bandler video seminars, and also Ross Jeffries. Ross Jefferies is focused for getting girls but if you can learn how to use his techniques with girls you can apply the same techniques to business and communication.
I think above all else it is important to practice what you learn. Just listening and studying will do little. Im sure you local "toast masters" club around where you live where you can practice talking in front of a group of people to build your confidence.
-Benny
