Are you able to practice at the site you'll be giving the presentation? Scoping out the actual location, getting a feel for the place, etc can be a big help. Public speaking is the most common 'phobia' there is. In the future, taking a public speaking course at your local community college can help. The instructor I had, made us read up front first(a piece of literture we liked to last for 3 minutes) and by the end of the semester, we were fielding questions and answers. Talk to colleagues who make it look so easy and ask them what tips they may have. You're not alone in this one!

If you are not afraid of meds, beta blockers work great for public speaking. Many famous people are said to have taken them in order to give speeches...I take a low dose beta to help with my anxiety

Im the same, terrified but always manage to get through them and no-one seems to notice i'm a gibbering wreck! Being well prepared helps, know yr stuff & get your slides / Powerpoint sorted it should lead you through without worrying about forgetting things. Also try to concentrate on the subject matter not on how yr feeling (not easy!) and try to speak slowly and 'look' relaxed. Finally try and think about the relief when its all over!! Good luck, y'll be fine :-)

PS - Mark Twain once said:
"there are two types of public speakers, ones who are nervous and liars"
Everyone is nervous no matter how calm they look.

Hey PFrye,
Yes, I agree with XTjohn, try to practice the speech or the presentation at the site that you'll be speaking at..if not, then practice in front of a mirror, or practice in front of your family, or some friends, and ask them for their feedback. This way, you'll start to get used to speaking in front of others. What else, my dad always told me to picture the audience in their underwear, sitting on toilets, and that always made me laugh. I think the big thing is organization and preparation. Be organized and prepared, and be on time! ALSO, DO NOT have any caffeine the day of the presentations...at work, when I was learning about speeches, they said that even though it's fun and cool to go to Starbucks in the morning to get a coffee or even decaf coffee...SKIP caffeine all together..because it makes anxiety worse.
You'll do well, just be prepared, organized, on time, no caffeine, and if possible get their early to relax, and feel out the scene. P.S. take some note cards to keep you on track! Good luck!