As a longer term project, if you think you are going to have to do regular "stand up and speak" sessions or presentations, try to find an Adult Education course in Public Speaking. It will seem a little daunting at first, but being with a group of people who are all suffering from the same nervous problem of speaking will give you moral support. You will be given short speaking exercises to do - often like standing up and talking in front of everybody for just one minute on a certain topic, but over time your nerves will gradually disappear as you become more confident and learn techniques to help you relax and control your breathing. Meanwhile, try practising on your own at home, or with your family. It may seem a little daunting at first, but family or friends can point out to you any obvious flaws or mannerisms of which you were unaware and it's better to try and overcome these in advance if possible.