At Manchester we had 5 official questions and 1 at the beginning (which wasn't marked) to help us relax.
We had;
Why Manchester?
What qualitites do you have that would make you a good children's nurse?
How has your voluntary work/work experience enhanced your communication skills?
What do you think would be the hardest part of studying to be a children's nurse?
How do you think children feel when they are admitted to hospital?
You're expected to prepare, but not too much or it sounds rehearsed! Remember that part of the reason for interview is to test your ability to answer coherantly whilst under pressure, not your ability to remember and spew out something you wrote before hand.