If you want to control fan speed according to CPU, GPU, Harddisk or Memory temperature there is very little nice tool ready to install in Ubuntu. I previously used the Windows version under XP and helped me a lot. Linux version is only command line but can be merged with some monitorin utilities. I won’t go into that but I will tell you how to setup and avoid a common error of i8kutils.
1) From SPM setup i8kutils
2) when you try to run any tools come with it you might get an error as “can’t open /proc/i8k”. If not go step 4, if you get the error read step 3.
3) Do these two easy steps:
modprobe i8k force=1
cat /proc/i8k
4) Now you can run it without problem.
The info howto use it is at http://www.diefer.de/i8kfan/i8kfan.html