Links to overclocking tools

Software tools only work if you have a motherboard chipset which supports them. If you have an nVidia nForce chipset, I recommend nTune. If you have something else, check with the manufacturer of the motherboard and they may be able to recommend a program which can overclock for you.

As a rule I do not recommend overclocking blindly. If you do overclock, make sure you do it safely and be aware that you are voiding the warranty of both your CPU and RAM (unless your memory warranty states otherwise).

Overclocking can be done safely and I recommend you keep a guide closeby when attempting it for the first and 100th times. You can find a guide in this issue of Maximum PC.