Now that I've got your attention, PC Stats have two overclocking guides for beginners. One covers video cards, the other CPU overclocking (and of course the memory and motherboard tweaking that comes with it.)

Overclocking the Videocard
Videocard overclocking can hold many benefits for the gamer or benchmarking enthusiast. As with processors and system memory, the faster the videocard's graphics processor and video memory can process information, the better. Smoother frame rates and higher benchmarks might be just around the corner.
Overclocking the CPU, Motherboard & Memory
The prospect of overclocking a computer system can be intimidating for a computer newcomer, to say the least. The idea is simple enough; make the computer's processor run faster than its stock speed to gain more performance without paying for it. The execution of this idea though, can be anything but simple.