Nintendo Inc. (TYO: 7974.OS) will release its hit video game Wii Fit in the U.S. on Monday. It is forecast to be the next blockbuster game after last month's "Grand Theft Auto 4"

Wii Fit, which costs $89.99, is currently sold out in preorder sales on Amazon.com and the Web sites of retailers GameStop and Wal-Mart Stores, while Best Buy's Web site lists it as "coming soon."

Wii Fit comes with a balance board, which is similar to their technologically-advanced wireless controllers. During the game, the balance board becomes a snowboard, skis or a tightrope. The game's fitness regimen includes yoga, aerobics and strength training, as well as tracking of your weight and body mass index.

"Our main premise in creating Wii Fit was (to) create a game that allows you to check your weight," Shigeru Miyamoto, the legendary game designer behind Mario and Zelda, told The Associated Press.