The bus system in Seoul was re-organized by then Mayor Lee Myung Bak (currently President). When I first visited Korea in 1993, buses were to be avoided because they made no sense and skipped your stop. Now there are maps at every bus stop and posted inside each bus.

Buses are color-coded by coverage area: Red buses are long distance, connecting Seoul and outlying suburbs. Blue buses criss-cross Seoul, think city bus. Green buses get you around the vicinity only (동), think local bus.

Bus fare begins at 900W and includes a transfer to another bus or the subway when using a T-Money Card. Public transportation has seats reserved for the elderly, disabled and pregnant. On the bus, they are located near the front. On the subway, they are at the end of each car. Be sure to offer your seat to anyone who needs it more than you do. Should you show such kindness, that person will likely insist that you set your purse/backpack on their lap to lighten your own load ~strange to a gyopo, but nothing will be stolen.