G.E. Watkins has a great article for those who are facing the challenge of leading a public prayer.
I don’t have a clear memory of the first time I led a prayer, just impressions. Those impressions are of fear, failure and shame. I was baptized when I was fifteen or so and I was big for my age (near six feet and over 200 pounds). This is all just to say, I know what you’re going through, I’ve been there. I’ve felt the dread, the sweaty palms, all of it.
The author gives some great tips on finding the courage and being prepared.
This for our Year of Prayer in 2009.