Core i7 overclocking on asus p6t-se

Hi,

i was thinking of overclocking my system but wanted someone with the right knowledge to point me in the right direction...system spec's are as follows.

Asus p6t-se(bios updated in dec)
core i7 920 (Do)bloomfield.
g.skill 1333mhz ram (1.5-1.6v) x3@2gb but running xp at present so aware of the limitation.
4870x2 gainward
scout case(cooler master) with extra case fans
Arctic cooling freezer extreme rev 2.
running 2 hard drives 1 ssd @ 40 gig for my operating system and one @ 500 gig for everything else.

i have tried to overclock in the past but i think to get the most out of my machine i need to learn about ram timings and voltages etc

any help greatfully appreciated...