Q6700 runs a 1066FSB (266 quad pumped) at 2.66Ghz stock.
Multiplier is 10 (10X266 = 2.66Ghz)
Raising the FSB in increments up to 333 (which would be 1333) gives you 3.33Ghz ... a plenty decent overclock if you can achieve it without much of a voltage increase to the CPU.
Note the older Kenty CPU's are rated at 105 Watts and the newer Q9 series are about 10 to 15 watts lower at the equivalent speed so when you overclock it be prepared to manage increased thermals ... so monitor it and don't go mad with the increase in voltage to get a higher overclock at the expense of a BBQ.
Boot to the bios <DEL> and go into Advanced / Advanced Processor Options (Page 4-6 in your manual) and change the FSB up from the default 266 to 333.
You will likely need to slightly increase the CPU voltage ...
In saying that I can't find where the FSB can be changed.
It does mention :Adjustable CPU clock frequency ratio (Only available if CPU is supported)
Take a look and update your bios first - to the latest supported ... which might open those options.