This is a list of express or non-stop bus destinations and times from Dong Seoul bus terminal in Seoul, which can be reached at Gangbyeon station, next to Technomart.
Accurate as of January 2011.
This link takes you to the official page for the terminal which has a schedule system. Kobus in English has a schedule listing for Dong Seoul as well.
EasyTicket in Korean also lists schedules from DongSeoul. Does not work AT ALL under firefox or Chrome but if you have IETab it does work.
This website here and this one here has more detailed listings from Dong Seoul as well. You just have to select Dong Seoul 동서울 first to get the proper listings.