Your Motherboard and stock HSF wont allow you too much overclocking room. But as Damn has said above, read up all information you can on overclocking, there's plenty of info out there. If you are enthusiastic, then you'll enjoy the process.
your motherboard bios has auto overclocking options.
i would not advice overclocking with that board.
the board already overvolts the cpus by default..
the Vcore is somewhere near 1.325-1.35V for X2 240s and this board will be provides 1.4V by default.. as per observation on past 6-7 boards.
All caps are electrolyte so if at all you want to overclock, do not shoot for the extremes, be careful and alway try keep an eye on the voltages and temperatures while to experiment with it.