The song is actually a cover of Radiohead's Creep by Belgian girls' choir Scala & Kolacny Brothers with Stijn Kolacny as conductor and brother Steven as pianist.
SIDE NOTE!: The first time I saw The Social Network trailer, this song was stuck in my head. What a great cover! The fact that adolescent girls are shouting the f-bomb in harmony is a little alarming, but I can take it.