It's about 79 dollars. http://en.wikipedia.org/wiki/Wii_Fit
I think Japan is the only country that has it now. I wonder why there's no release date for the U.S. while there's one for the U.K. It's usually the other way around. Maybe, they think it won't be a hit in the States because we have too many fat people?
I've been doing something similar like this for a while now. Since I have wireless remote control for my PS2, I do hula hoop while playing games. Nevertheless, it only helps the waist. I still have thighs, butt, arms, and chest to work on. That's why I'm so glad to hear about this game; I've been waiting for something like this for a long time.