What is an interview?
Simply an opportunity for two or more people to find out about each other. 'Interviews' are a part of every day life, not something to be worried about.
A two way process...
Remember that your are interviewing the prospective company as well. Do you want to work there? Don't be afraid to ask the right questions.
An interview is an ideal opportunity to learn more about the job role, the company and the people you might be working with.