I suggest you find out the PLL IC, try Sisoft Sandra mainboard information, if it is an ICS950201 then you need to mod the board to OC as this PLL is not software programmable. If it is another type then you may be able to use CPUFSB or something similar to manipulate the FSB speed.
Generally Intel boards are not designed to OC, but with enough effort it is usually possible, I would advise another mobo though if you are serious about overclocking.