I used to think that when you present you have to become this super exciting, amazingly charismatic personality and it would make me feel that I wasn't able to do it.
However, I learned by observing good speakers that if you are pretending to be someone you are not it shows! What makes a speaker good, is when they are simply having a conversation with the audience, they just happen to be standing up at the time.
You probably do that every day without realising it. How many times have you walked past someone's desk and they asked you a question and you answered it while they were sitting down and you were standing up. It's the same dynamic. They wanted to know something and you told them the answer. That's presenting! Change the way you think about presenting and you will find it easier.
When it comes to preparing your presentation you'll find that 10-15 minutes really isn't that long to say what you want to say. To keep it simply imagine you are presenting on 'splorks'.
Base your presentation answering questions on splorks that begin, who, what, why, when, how and who. Allow a couple of minutes per question and you are already at your time!
What are splorks?
How do splorks work in theory and in practise?
Why are you interested in splorks?
Who is the leading authority on splorks and what does she or he think about them?
When were splorks first discovered?
Where can you find out more about splorks?
What are your personal recommendations about splorks for the company you are applying to?
If you really want this job, you'll find a way to get yourself up there. If you need speaking lessons you'll get them or get help any way you can, there will be someone you know who will help you prepare for the interview. I recommend a book called 'Great Answers to Tough Interview Questions. (sorry forgotten author, but is on amazon) that you can read so that you have mentally prepared outline answers to the most obvious interview questions.
And when I feel like curling up and hiding I remember this quote from Marianne Williamson "Your playing small doesn't serve the world". Marianne Williamson - Wikiquote
Good luck - and enjoy it!