Overclocking is NOT recommended. Still, if you wish to go for it:
1. Check out your present CPU and system temperatures.
Reason: If they are low, you have room to make things hotter for them; otherwise first make your system cool enough to take a little extra heat. Otherwise, prepare for some fried silicon.
If things are cool enough, try increasing the processor FSB by 1 MHz increments.
Suppose we start at 200 MHz which was listed as default. Make it 201, boot again. Booted properly? Try 202. And so on. Suppose at 230 the system did not boot. Now you know that this is the limit. Clear your CMOS by removing the battery, wait two seconds, put it back in.
Set your CPU fsb to 229 assuming it booted fine in that setting (it had to, otherwise we would not have been able to set it to 230, right?

). Now you have a successful overclock session.
Test it by playing a nice game like Half Life 2 or any other which tends to choke the system bandwidth.
2. Suppose the system had booted fine into windows at 229 fsb, but the game you played gave you a blue screen. This simply means that the system could not handle that fsb, reduce it to 228 and continue with the game. Supposing it went fine without problems, you are now the proud owner of an overclocked system which is both safe and stable.
Thank you.