I'm taking a public speaking course this semester (required for my major - not out of my own free will, heh) and one of the first things the professor pointed out was that the majority of people are more afraid of public speaking than of dying - myself included.
Honestly, I'm pretty good at getting up and talking to a group of people - as long as it's not really planned, and not for a grade. If the "speech" falls under one of those two situations, I freeze. I can speak and I can breathe in, but I can't exhale. Which makes speaking in a normal voice pretty hard to do.
I have a persuasive speech coming up soemtime soon, and we have to give it twice; the first time, to our class (no big deal) but the second time, we have to pick somewhere on campus and just stand up and start speaking.

Most of the class is seriously thinking about not giving their speech the second time and dealing with the automatic 10% grade loss. As for me? I'm not even sure
what to give my speech on. I had a topic in mind, but she changed the requirement to be something "Earth Day" ... -esque.
*sigh*