Talented Technically

I have some phobia, public speaking. I don't understand i'm very nervous in my meeting room. I am very talented technically. i have good communication skills than any one else in my team but i am unable to project what i am. whats wrong with me.... i feel very nervous, my hands will shake if i try to speak some thing in meeting rooms. please help me to get out of this phobia because its very important for me to speak with out any phobia.