Seoul Metro Map (New)
This is quite mostly up dated Seoul Metro Map.
From Incheon Airport to Hongik University station, it takes 1hour.
I recommend buying a T-money card(2$ USD) and top up.
T-money is very useful.
Most people use credit card instead T-money,
but for travelers T-money is enough.
(You can spend money in 24 hour convenient store!!!)