I have a core 2 duo and a abit fatality motherboard, all cooled by a zalman 9700 cooler.

ive heard the core 2 duo series are highly overclockable, however i have never overclocked before , and dont know where to start
just wondering you have any guide or know of any that could be useful and directly relates to my motherboard is Fatal1ty F-I90HD

With the speed of today's processors, it's hardly worth the effort and the extra stress on the system. Here's some sites that has articles on the subject:

Overclocking Tutorial

CPU Central

Overclocking Madness

A search on overclocking will produce a lot of results.