Nintendo said it sold more than 15 million units of its blockbuster "Wii Fit" fitness game, and plans an update -- the Wii Fit Plus -- later this year.
Sales of the Wii have dwarfed those of more technically souped-up and pricier rival consoles from Microsoft Corp and Sony Corp, by broadening its audience beyond hard-core video gamers.
On the second day of E3, the largest US video games conference, Sony and Nintendo vied for the spotlight, a day after rival console-maker Microsoft charmed audiences with its "Natal": groundbreaking technology utilizing full-body motion-capture for gamers.
