Money exchange (In Seoul)

Im going to visit South Korea next week. It's my first time to go there so I'd like to know about the money exchange. Where is the best place for currency exchange? (In Seoul) Any suggestion about it?
Thank you in advance,
Piraya.

Incheon Airport's lower level has several very good exchange facilities. If you plan on later using an ATM, just be aware that Korean ATM's only have a numeric keyboard.

Firstly shop the banks, but i think the currency will be generally same.
(do not change your money at the shop. the rate will be poor)

Thank you very much for your kind suggestion.
It's very helpful for my first time trip over there.
Have a nice day n Enjoys,
Piraya.