[Q] Overclock topic

Hi everyone, I want to overclock my Galaxy mini S5570 so anyone can help me with this, can anyone explain step by step, I really don't know about my galaxy's/smartphone's mhz, can anyone tell me how much is it as normally ?:confused::confused::confused:

One more thing, what would be demerits and merits of overclocking ? :confused::confused::confused:

I've rooted my device, and android version is gingerbread 2.3.6. :fingers-crossed::fingers-crossed::fingers-crossed: