Want to talk about your hardware setup? Brag about your super-machine's layout? Pretend you know a lot about computers? You can do all that and more in this forum.
I have never overclocked my computer. It makes the computer just a little quicker but you can get a lot of problems in the longrun. I have heard of computers overloading by overclocking.
Overclocking your computer won't harm it, as long as you know what to do to keep it cool. Adding another fan would probably help. Now, I've never overclocked my processor, though plan to do so sometime in the future. In my computer, I have an AMD Athlon 64 3700+ processor currently clocking at 2.1 GHz. Overclocking would help with running newer games that require high speeds and things of the such.
A google search for "overclocking processor" might help.