THE JTIZZLE  great little app, has made my MacBook Pro run almost 20 degrees cooler with the default settings and only increased my Fan RPMs by 500.  
(Version 1.2)

L0XBY  if you have a late 2006 imac (model: imac5,1), the derman fan control app will not adjust the cpu fan automatically (his version measures the CPU heatsink and not the actual CPU temp, so you never see a red dot on the graph).

i have fixed the source code and recompiled the installer. i've also adjusted the max fan speeds so that the cpu fan spins up faster than the hdd fan. that way, less hot air is blown onto the power supply unit by the hdd fan, and more air is directed to the logic board where the GPU sits (for the ATI X1600).

here's the link to the revised installer:

http://bit.ly/5lPCI3

only use this if you have a late 2006 white intel imac.   
(Version 1.2)

GSC  DO NOT INSTALL THE DERMAN VERSION

I installed the Derman version for the imac and found that it irreversibly set the minimum fan speeds higher than the factory settings. When I asked them for help to uninstall their software, they refused and instead said I should google various forums looking for tips. Apparently, Derman Enterprises (which I think is just one guy named Bryan) has defined a new software category called "unsupported" where they put out software with the stated intention of helping but then seemingly get a kick out of letting troubled users fend for themselves. I've installed lots of freeware/shareware where the developers are more than happy to help. If you search Derman, reviews on all their software are very mixed, which I now understand.

Fortunately, the folks at lobotomo are principled and actually provide instructions for uninstalling and resetting: http://www.lobotomo.com/products/FanControl/

I will never again install anything from Derman.  
(Version 1.2)

RUBAIYAT  I found http://www.derman.com/iMac-Fan-Control to give better control.  
(Version 1.2)

JOHNGALT3534  I performed a CPU upgrade on my mac mini. 1.66ghz cd to 2.33ghz c2d. after installation, the fan did not run at all and Fan Control posted 0 degrees temp.. I was going to crack the case open again and look for the problem. But before I started I uninstalled Fan Control via the posted instructions. I then re-installed and voila, the fan works great and temp. readings are optimal.  
(Version 1.2)

NUBNUB  Same problem.

Macbook pro 13". Deleted using fan control instructions. Also reset SMC. fan will not increase speed even at 70c. Reinstalled. and fan turns back on. This needs to be fixed.

Also, what happens if i want to reformat my computer? Will i need to install fan control again? Will the firmware be reset if i reformat my computer?  
(Version 1.2)

KERSEY84  I have the same problem as Eli. Can someone please help us? Greatly appreciated. =)  
(Version 1.2)

ELI LEVINSON  I have dowloaded the file and then installed it using mac install or whatever but i cant get the actual fan control window with the bars and graphs to open.

Thanks  
(Version 1.2)

STEVE BURNS  This is a great app!! Problem I have is that it will not ever set the fans to the max rpm of 6200 for my MacBook Pro 15" unibody. Seems only to get to about 5800. The red line on the graph in the system preferences control panel even indicates it will never use 6200.

Anyone got any solutions?

thanks!  
(Version 1.2)

MAX Z.  I noticed that one will have problems with uninstalling this program and restoring the original system settings. I highly recommend to use this program if you are using a laptop, because it drastically cools down the CPU.

So to solve the problem of not restoring system settings after erasing the program, all one has to do is to set the cooling preferences to the Apple settings (1500 RPM, Lower Th. 50°C, Higher Th. 80°C) and then erase the application.

Have fun. And stay cool.

Max  
(Version 1.2)