Japanese software sales thus far (Famitsu)

– Wii Sports (Wii, Nintendo): 2,998,097 copies sold
Release: 12/2/06

– Mario Kart DS (NDS, Nintendo): 3,103,810 copies sold
Release: 12/8/05

– New Super Mario Bros. (NDS, Nintendo): 5,203,488 copies sold
Release: 5/25/06

– Animal Crossing: Wild World (NDS, Nintendo): 4,675,540 copies sold
Release: 11/23/05

Source