Hey, not laughing here! You're not the only one in the dark. Many folks out there know the word OC and use it freely, but ask 'em how and you get a quote from a magazine or site. But do they understand it? Nahh...
Learn the basics of how a PC works first, then it'll all click. Basically, there's a Front Side Bus (FSB) clock that is generated by the northbridge (chipset). It tells the bus to run at, say, 200Mhz. Then, the CPU has what's called a multiplier. This is a setpoint that the vendor set internally to tell the CPU how fast to run. If it's set at x10, then you take TEN and MULTIPLY it by the FSB...2,000Mhz.
The multiplier is now locked down and you can't change it (except in older AMD's. And newer Intels combined with certain motherboards and the correct BIOS, they'll let you lower the multiplier). SO, the basic way to OC is to simply bump the FSB up. SO, you can't change the 10, so change the FSB. Bump the 200 to a 210 and you now have 2,100Mhz. That's an Overclock in short.
You still need to understand more before you jump in head first. Small bumps are a gimme (10Mhz bump as above). Big ones need more knowledge as you'll be having to see and understand what's going on in order to correct it. You can't make a Chevy V8 spin 9,000RPM by reading a how-to in Hot Rod magazine
If anything, it's a chance to understand what actually goes on inside that PC. If OC'ing sparks this interest, then by all means educate and continue! Questions to ask along the way: What's timing? What's PC533 and PC4200? Is there a difference? Why would you want to LOWER a multiplier? What's bandwidth? What's being stressed? Where? What's power consumption? What's a class Alpha fire? ¿Dónde es el nearist casa de la puta?