Ok, well I'm sure you're familiar with the bios menu then. First you want to bump up your fsb maybe 5fsb, at a time, until you get about a 10% overclock. That would put you at about 3.3Ghz. At that point it may be wise to bump up the fsb by 1-2 each time you restart. You need to find out where your system stops maintaining stability on stock voltage. To make sure your voltage isnt automatically changed from overclocking, you want to put vcore on manual. I'd say a good number to set it to would be 1.4.
I think the biggest issue with overclocking those processors is the heat. I hope you have decent cooling. Remember that there is always risk in overclocking your cpu or any other main component in your computer. The main killer of pc's is heat. Remember that