1)What is overclocking?
2)How to overclock?
3)What do I need for overclocking
4)Advantages and disadvantages of overclocking
1. Running your hardware at speeds or settings in excess of rated.
2. Depends on hardware and individual knowledge.
3. Hardware, time to learn OC, the will to do it, and a bank account to replace things that lack of preparation (or impatience) causes you to destroy.
4. Adv: Zero to moderate performance gains, bragging rights, knowledge about hardware operation.
Dis: Time spent (lots of it), system instability, system failure, hardware destruction (if not disciplined), software incompatibility
In this forum, I personally won't even begin to touch the topic of introductory OC... but google is a good way to find lots of sites about it. Take a month or two, and just read and absorb. Know the system interactions of increasing frequencies, e.g. Know what 2-2-2-5-1T means. Know why some boards are better than others for OC. Know what unlocking a CPU does.
There are some experienced OCers in this forum (2 have already posted, I see). If any potential OCer does their homework, then has a direct question, I'd answer it, but I won't touch the beginner aspect of it... people will try it and then destroy something; entire websites are devoted to it, and it is very hardware specific.
As for general RTW/BI stuff, people in general have enough problems just getting it running smooth, optimized, and stable without OC settings... throw that in, and all other bets and troubleshooting are off. The experienced OCers can already read a troubleshooting procedure, and know what they have to do/allow for when testing video card settings, for example. That's why all procedures & HOWTOs I personally post assume no OCing. That's not to say that you can't... but you must know how its going to affect you, and account for it. So OCing will complicate things considerably... but with the time and effort, it is not "rocket science"... for the careless or hasty, though, it can be "pocket science"... money from your pocket to your local computer dealer!
And one more thing... OCing for most people will require certain hardware to make an impact (like certain RAM) without reducing stability. The performance gained on low-grade stock in mose cases is trivial compared to simply putting the effort into optimizing your registry, disk drive, swapfile, system settings, etc. The downside of the latter is at most a system reinstall, not hardware destruction and hardware upgrades. So its much less expensive.