Get at least a "four star" rank on the indicated song in the listed Campaign mode stage to unlock them.
Stage 1: "Fight the Power" by Public Enemy.
Stage 2: "Big Poppa" by The Notorious B.I.G.
Stage 3: "Lean Back" by Fat Joe.
Stage 4: "It Takes Two" by Rob Base.
Stage 5: "Put Your Hands Where My Eyes Could See" by Busta Rhymes.