what bettytheyeti said. seconded, and all of that.
the 560 is a sound transit bus, i.e. not metro. it originates in the alaska junction, at 44th and alaska, behind the wells fargo bank. the route goes down california to morgan jct, down fauntleroy, past the ferry dock, east on roxbury, down ambaum blvd to b-town, then to seatac.
from what i remember, the travel time is just over 30 minutes.
http://www.soundtransit.org/Schedules/ST-Express-Bus/560.xml