Another great way to start your public speaking career is to go out onto the Rotary circut and practice giving your speech for free. You will get a great chance to refine what you have to say, infront of people who can make decisions.
Here is a tip for removing Um's err's and ahs that you wont find anywhere else.
Practive speaking to a group for 1 minute without using any words either starting or ending with the letter "N". This will help you organise the words you are going to say and this will help you reduce the filler words!