I hassled with it several years ago. I recall it being more difficut than I thought it should be. I can give you some pointers to get started begin with the manual, use:
in a terminal. As I recall, you need a configuration /etc/i8kmon.conf (or maybe just /etc/i8kmon) you can copy the one from /usr/share/doc/i8kutils/examples
Hopefully someone can provide more detail later... but I hope this can help