For a nice overview of cycling (and self-powered touring generally) in the Netherlands, get a copy of The Backroads of Holland by Helen Colijn, published by Bicycle Books Inc., Mill Valley, California (ISBN #0-933201-44-3). Lots of good info on the country and culture, presented with a great attitude. And I'll second (or third or fourth) the suggestions made previously in this group to get the ANWB maps; they publish a fantastic series of map kits for regional bike touring, though the text in the accompanying booklets is all in Dutch. Don't know where you can buy these in the U.S., unfortunately.
--Andy--