Have a read of as many guides as you can find - make sure you know what you're doing before you start! BTW overclocking in the BIOS is far safer than doing it in Windows - less chance of corruption of files etc. Don't be scared of the BIOS, as long as you don't change things randomly and then save the changes, you can't really go wrong.
So... although this is very simplified...
Find in the BIOS the HT multiplier (this may also be called the LDT multi - it is on mine). This will give options for 5x (default), 4x, 3x etc (these may be put as 1000, 800, 600 ...). Knock this down to 4x.
Find the RAM settings in the BIOS (do a google for you specific board - I don't know how it will appear on this BIOS) and find the RAM divider settings. Drop the divider.
Next, increase the FSB speed. Do this in 10MHz increments (or find what others have got to on that CPU and go to just below this figure and then do it gradually). Make sure that the FSB speed multiplied by the HT multi is 1000 or less - if it isn't drop the multi again. Watch you RAM timings to make sure they don't go to far over 200MHz (drop the RAM divider if they do).
If you get instability, try increasing the VCore a bit through the BIOS.
Try to find what other people have done with this CPU - it's by far the easiest way of doing things. Make sure you know how to reset the CMOS (there will be a jumper on the board allowing you to do this). Apart from that, good luck!