According to Japanese magazine Famistu, the Nintendo Wii crossed the '8 million sold' mark in Japan on April 19th.

Enterbrain has also released the top five selling Wii games in Japan (it's worth pointing out that Wii Sports was not bundled with the console):

1. Wii Sports
Launch: 12/2/06
Life-to-date: 3,481,469 copies

2. Wii Fit
Launch: 12/1/07
Life-to-date: 3,301,373 copies

3. Wii Play
Launch: 12/2/06
Life-to-date: 2,672,811 copies

4. Mario Kart Wii
Launch: 4/10/08
Life-to-date: 2,218,756 copies

5. Super Smash Bros. Brawl
Launch: 1/31/08
Life-to-date: 1,789,924 copies