Press the minus button on the Wii controller and enter the following codes for the noted outfits.

Left, Right, Left, Right, Left, Right - Detective Outfit
C, Z, C, Z, B, A, B, A - Tattoo Vest Outfit
Y,X,right,left,L,R,down,up - Samurai Armor
X,Y,R,L,X,Y,R,L - Samurai Helmet
Left, R, L, Right, Y, Y, X, X - Punk Bottom
Up, X, Down, Y, Left, L, Right, R - Punk Top