ICN to Busan... by bus?

Seems you want to go to stop 10C on the first / ground floor for a bus. Here are the details in English and Korean.

http://www.lifeinkorea.com/Travel2/IABIk.cfm

http://www.lifeinkorea.com/Travel2/IABIe.cfm

Alternatively you could just get one of the regular airport limousine buses that will take you direct to Seoul station where you can chill out in the comfort of the KTX. And consider upgrading to first class it's worth the extra 15-20 bucks after a long haul flight.

You do not want to take the bus. Takes forever. For someone worried about travelling for 24 hours you should just fly. Flights run for around 70 bucks-thats it. You can take one from Incheon but they are only in the morning and evening I believe. But from Gimpo they go every 30 minutes or so. Take the shuttle bus (right outside arivals in Incheon) to Gimpo airport and grab a flight.  You will be in Busan a whole lot faster this way than the bus. The flight is like 45 minutes. For a few exta bucks it is the only way to go.

The next best option is to take a bus to Seoul station and grab the KTX. For 50 bucks it ill get you here in 3 hours. The bus will take like 6 if you are lucky because of traffic. Take a plane-you wont regret it.

Take the bus from stop 10C outside the arrivals hall at Incheon. Takes 5.5 hours to Nopodong bus/subway station in the north of Busan. Long journey but you can sleep on the bus as the seats are luxury reclining and very comfortable. I always do this and its pure bliss after the economy airline seats back from Europe. Just make sure you bring a sleeping mask to block out the sun if its daytime. Price is about 40,000.

the bus from ICN to Busan is comfortable but if you want to catch a flight to Busan and need to get to Gimpo there is a train service (called Arex) connecting the airports.

It takes 33 minutes and is to the left when you enter the arrivals hall. it's probably quicker than the shuttle bus.

anybody know the cost or details for how to go from seoul station to incheon by shuttlebus/limo, whatever you call the airport shuttle?  thanks in advance

A few days late in replying. But for future reference. When you exit the gates at Seoul station head to the exit on your left, the opposite one from the one that takes you to the subway and taxi ranks. Descend the stairs or escalator to the road and turn left. The buses wait immediately there. Should be all signposted, too.