A few months ago a friend recommended smcFanControl, and I've been cool ever since. Cool as in temperature, not cool as in Mark Shuttleworth.
Macs are awesome, of course. This goes without saying. But it also goes without saying that you can fry eggs on the MacBook Pros (and the Powerbook G4s before them). I have third-degree burns from long blogging sessions.
Enter smcFanControl. It's a super-simple but powerful GPL program that allows you to take control of your MacBook Pro's fan. By default the RPMs won't exceed 3,000, but you can tweak this to go much higher. While I tend to not use the program on flights, where I want to preserve battery life, I use it religiously at home/work when I don't want my Mac to be the dominant source of heat in my home (though we are considering saving on heating costs by switching from natural gas to MacBook Pro.
Should you be worried about damaging your Mac? After all, doesn't Apple know best, and shouldn't it, exclusively, mess with your fan settings? Maybe. But the greater problem that I see--burning out your Mac, not your fan--is impossible with smcFanControl because it won't let you set the fan speed below (or above, for that matter) what Apple recommends.
In other words, you stay cool, and your Mac doesn't fry. I'll buy that (except, of course, I don't have to--it's free as in price and as in freedom).