Not sure about why you actually want to control the fanspeed but if its a noise issue the BIOS should have the option of powermanagement, this will automatically adjust fanspeed to keep temps at 45c or so. Disabling the fan features wil make the fan run at fullspeed, bit noisy but great if you are overclocking.
Speedfan isn't that great in my opinion, the temps are not correct, if you use Intel TAT which takes readings from the actual CPU they will be higher than speedfan. For £15 an Arctic freezer Pro is a great way to get the noise down, with PWM set in BIOS I had to shine a little torch on the fan to check its running as its so quiet, it carries heat away from the CPU so effectively the fan is off half the time!
Hope this helps