Having used an ACF7P with a Q6600, I can say that that cooler should let you reach 3.3 - 3.4 GHz, but probably not much farther.
This should be your first stop.
HOWTO: Overclock C2Q (Quads) and C2D (Duals) - Guide v1.6.1http://www.tomshardware.com/forum/240001-29-howto-overclock-quads-duals-guide
Next stop should be a guide for your particular motherboard. Google is your friend.
Some comments on OC'ing nVidia chipsets:
Overclocking 680i/780i chipsets:http://www.tomshardware.com/forum/263006-29-overclock-q6600-680i#t1884029