overclocking is increasing your CPU speed beyond what the stock speed is. Its not hard if you have a unlocked CPU (955 and up quad core AMD, 1090 and up Hex core AMD, 2500k and 2600k Intel), as you just increase the multiplier (how many times your BUS speed is multiplied to get CPU speed, 20*100 vs 22*100 would net 2GHz vs 2.2GHz.
If you do not wish to OC, then you are set. If you wish to OC, then you will need an aftermarket cooler and some better Paste, like AS5.