Update!
According to this site, Wii Fit Plus is at 7.6 million. It's got fantastic legs in Japan according to Media Create (it's still over 50k per week), and likely in North America as well (it did great last month, and likely will this month too).
According to this site, Wii Sports Resort has already surmounted the 10 million mark (11.84 million). I believe it's overtracked, or else Nintendo would have trumpeted this achievement, but I doubt it's that far off. It, too, has great legs in Japan (per M-C) and in North America (NPD).
According to this site, New Super Mario Brothers Wii is just short of the goal at 9.27 million. Again I suspect overtracking, but lord knows that game's on fire!