We don't know much about it yet but it will have a more western style workout than eastern style workout. Whatever that means? But here's 2 links
http://www.joystiq.com/2008/05/08/ea-sports-working-on-sweaty-wii-fit/
http://www.eurogamer.net/article.php?article_id=137758

PS If you don't know what Shamwow is, Here's a link.
http://www.getshamwow.com/Default.asp?bhcp=1