Japanese software sales so far (Famitsu)

– Dragon Quest V (NDS, Square Enix): 1,131,378 units sold
Release: 7/17/08

– Battlefield: Bad Company (PS2, EA): 29,112 units sold
Release: 8/28/08

– Mario Kart DS (NDS, Nintendo): 3,194,908 units sold
Release: 8/12/05

– Sigma Harmonics (NDS, Square Enix): 38,631 units sold
Release: 8/2108

– Wario Land: Shake It! (Wii, Nintendo): 91,743 units sold
Release: 7/24/08

Source