Here is what i did to get my OC.
Since I run a Asus M3A-32 motherboard I hit the Del key to go into the bios.
Head to the advance area to the jumper free section.
In there it pops up with setting things on either manual, auto, or overclock.
I set it all to manual which allows me to set voltages for my ram, north bridge, and processor separately. This also opens up the options for the multiplier for my north bridge (210), ram (set to standard clocks), and the multiplier for my cpu (standard at 17x oc'ed to 19.5).
Voltages are something you will have to look up for your own computer. My rams standard voltage is at 1.5v, your manual will tell you your north bridge voltage, and my cpu(1.43v is the base for the 965 and 1.5v is the ceiling of the chip).
I wouldn't bo beyond the 1.5v on the cpu unless your running liquid cooling.