Hilary Rosen paces the creaking oak floor of the Oxford Union debate hall, eyeing the empty pews the way a Roman gladiator might have surveyed the Colosseum. Rosen is the chair of the Recording Industry Association of America, and in a few hours she'll be standing here in a black formal gown, getting ripped to pieces. Along with several other industry executives, she's charged with defending the proposition: "This house believes that the free-music mentality is a threat to the future of music." Of course, the students of "this house" believe nothing of the sort. "I myself have about 900...