You're talking about the Arctic Cooling Freezer 7 Pro HSF, correct? If so, if you bought that HSF around the same time as you bought your Q6600 setup, then no it won't be compatible with your new setup. If you bought that HSF after September 2009, just look in the box that HSF came and look for any additional brackets.
Thanks guys.. Yeah I bought it back when I built the Q6600, but I thought it might have been around 2009, but I don't have a clue where the box is, and there was probably nothing in it anyway.
Looks like I am buying an aftermarket fan (the one that came with the processor powers on intermittently and returning the whole thing to wait for a new one with shipping etc just isn't worth it).