In music videos many times it looks like the singer is singing in slow motion but the video plays back at the right speed and the song lyrics he's singing match the actually song's speed. When they shoot the music video, are the band members playing at a faster speed and shot at a higher frame rate so when its played back at 24 fps, everything matches? Here's an example...
http://www.youtube.com/watch?v=9zGyIdlvzpg
http://www.youtube.com/watch?v=9zGyIdlvzpg