Kae-maN

i was looking at the alpine subs and im wondering whats the difference between 2 ohm and 4 ohm subs?
also amp wise my buddy said to pick up a mono amp so i was looking into them and i just dont understand the specs of the amps i was looking at.. how many watts do i need my amp to output to the sub? and i realize that the answer will reflect the amount of ohms of the sub i buy which is why i need that question answered aswell