PS3 current sales (retail, not shipments) - 31.76 Million
Wii Fit Plus + Wii Fit = 32.2 Million
According to the latest Nintendo report of sales, the majority of Wii Fit Plus sales come from the balance board bundle, not the standalone game, so it might be safe to assume that Balance Board already surpassed the PS3 instaled base, or at least is very very close to achieve that.
Is it the first time in history that an expensive peripheral surpasses the sales of a major home console?
This is impressive!