This is from the official documentation for using Ubuntu on an eeePC
In order to achieve the overclocking we'll need to compile a kernel module available for download at a Google code site.
You'll most likely need the kernel headers installed as well as build-essential before we can get started:
sudo apt-get install build-essential linux-headers-generic
Download the source, and create the module:
wget http://eeepc-linux.googlecode.com/files/eeepc-linux-0.2.tar.gz
tar -xf eeepc-linux-0.2.tar.gz
cd eeepc-linux/module
make
You should now have a file called eee.ko. To make this module a permanent fixture of your current kernel we'll add it to the list of modules that are loaded at boot time and move it to the proper location.
sudo mv eee.ko /lib/modules/$(uname -r)/kernel/
Then edit the /etc/modules file and add the module name eee to the end of the file.
Next register and load the new module into the kernel.
sudo depmod -a
sudo modprobe eee
In general, jumping directly to the overclocked speed can cause lockups so smaller jumps toward the speed are suggested. Below is an example of gradually making your way to the overclocked speed:
sudo sh -c 'echo 85 24 1 > /proc/eee/fsb'
sudo sh -c 'echo 100 24 1 > /proc/eee/fsb'
echo "FSB overclocked to 100MHz"
And going back down to the default speeds again:
sudo sh -c 'echo 85 24 1 > /proc/eee/fsb'
sudo sh -c 'echo 70 24 1 > /proc/eee/fsb'
echo "FSB returned to 70MHz"