Factual error: In the scene where Billy's brother argues with a miner in the local shop, there is a plastic Polo dispenser that wasn't around in 1984.
Factual error: The grown up Billy in the end of the movie has brown eyes where as Jamie Bell's (Billy's) eyes are blue.
Factual error: After Billy dances in the gym in front of his father, he goes out in the cold, everything is covered in snow, but no steam comes out of his mouth...
Answer: It's called 'I Will Dance' by Stephen Warbeck.