From my experiance its not the actual speech that brings on the panic and anxiety of a presentaiton while your standing up there, its how much knowledge you've memorized so that once your up there giving the presentation at least you can have a conceptual idea of what your presenting ..that means even if you stutter or become agitated you'll still have it all upstairs in your brain, or enough of the information that you'll at least be able to articulate it even if your mumbling, you can give the audience something to walk away with ...
many of my unmemorable presentationts came from just not knowing enough or doing enough homework, so i'd repeat what i'd already stated in previous sentences, looking like a complete doozy standing up there with not alot to present, then i'd guess and make up things just to fill in time...
so you need to be EXTRA confident in the content even if that means practicing infront of a mirror or a friend, give yourself some opening and closing sentences ...
what you'll discover is that the knowledge far outweighs the initial nevers of standing up there having to talk infront of people
Drink plenty of water before and on the day, as you may experiance intense sweating and thus dehydrate and spin out ...it calms you down alot ...
While your at it watch this queens of the stone age video below, please, for the sake of humanity and the starving children
http://youtube.com/watch?v=Y9Z2NtmVQ7I