Simply put, over clocking is the process of running your system faster than the speed its been rated for. In most cases, no physical harm will come to your computer - worst case is the machine will lock up upon boot up, or be so unstable that you have to reboot and rethink your over clocking strategy. We will touch upon how to combat this problem shortly. 2x - so avoid these. But there are still a few gains to be made.
Second requirement is the motherboard.
Obviously, the better quality motherboard, the better your chance of success will be. The better the motherboard, the less likely you will experience dirty signals on the system bus - this works both ways, as the faster the cpu runs, the more likely it is to introduce dirty signals, and the faster the motherboard runs, the more likely it is to run unstably. A new wrinkle in all this comes with the new motherboards that have 100MHz busses on them. You will find this new faster bus speed on Pentium II motherboards with the BX chipset. I have one of these on order right now, so perhaps I can give an update at the next meeting or post my findings on the web version newsletter if you're interested.