In simplest words mining means the procedure which use to verify the transactions of a coin by solving a mathematical calculation. It is a complex process. For mining you need Good GPU (VGA Cards), Low cost but constant electricity supply & related mining software. If you think to mine coins through your normal PC without High-end GPUs, then it will be really useless because you can't get much profit with CPU. GPUs use high electricity power & emits large amount of heat. If your living in a cold environment, then it will be OK. But otherwise you'll need to A/C the room because of that high temperature. GPUs + A/C use much more electricity than you think. Because of that you need to have low cost electricity power.
If you need more details, please take a look at here:
https://bitcointalk.org/index.php?board=14.0