I second what Steely Dan said although I always use the train -- it's in the basement as you come out of the main airport exit so incredibly convenient and very frequent. Strangely, the most respectable whores are probably the streetwalkers (especially daytime). Very safe, they take you to a nearby flat. That, and the fact that almost anything else is just ridiculously expensive.
As SD said, out of the station, cross over (or under if you prefer) the concourse with trams and what-not, straight ahead down the main street (ie at right angles to the station) and the busiest bits are around second or third street down on your left, and a long one that runs parallel to that main street.