I found this while troubleshooting the CPU problem a lot of us mac users are having. I guess some people got together and progressively created this app that works way better than turning up the fan in osx and booting windows:
Lubbo's Macbook Pro Fan Controller
this works on my macbook pro 15" unibody. if it doesn't work there's a link on the forum link below for an app called macfan, but I haven't tested it.
here's the
original forum posting about it all if you're interested.