I would like to become an ESL instructor to adults, but I have a major fear of public speaking. Did any of you have this problem, also? If so, how did you overcome it?

Definitely! I cried on my first day. Not in front of the students but the secretary. I still get nervous every once in awhile. It's natural.

oh yeah!!! its repetition it gets easier until it becomes part of u and pretty natural.

It is not abnormal to have it! What you need to ponder over is how to overcome it! For instance, before you enter a classroom, remember that you're going to be watched by so many eyes but you have only two eyes to watch all of them! Grab their attention and sow the seeds for growing their confidence in you by having a glimpse of or glance at every pair of those eyes before you start saying anything to them! Your initial stage fright, if any, will be behind you! Good luck in your planned career and welcome aboard!

Haha, I still have stage fright!! But there is something about being "on stage" that calms me down once I begin to talk. You ease into it, and you'll be fine!!!!!
Plus, where I am from ESL classes for adults are rather smallso if you start small, it may be easier to manage your fear. And then, you can work up to bigger classes.

Oh yeah.
My first day, my bra strap started sliding down my shoulder, past my short-shirt sleeve...I didn't know what to do. I couldn't focus, didn't feel like I could fix it, just frozen. Uh uh uh uh.
It gets easier. Trial by fire.

I taught the obscure and difficult subject of Acupuncture to adult students. I did what a great comedian said he did: I visualized them all in their underwear. Also, in Chinese Philosophy there is a chapter in the Tao Te Ching that I applied...Approximately: in life, three in ten people are following a path of life, three in ten are following a path of death, and those just passing by are also three in ten...but then there is that one who knows how to live...I taught towards the one in ten, I spoke to the three following a path of life, and I allowed the other six to just sit there and pay the bills. Enjoy!

Its pretty normal to fear that...but with time and practice you start being able to handle it... don't worry... :)