An invaluable resource for non-Dutch speakers visiting Amsterdam and the Netherlands, a door-to-door public transportation journey planner is now available in English at http://journeyplanner.9292.nl/
The itinerary generator covers all methods of public transportation across the Netherlands, including train, metro, tram, bus and ferry. Your starting and ending points may be an address, a museum/attraction, an airport, a station, etc. But I've found the results much more helpful when using a specific address for places like museums.
The planner doesn't just suggest the methods and routes for your journey, it also builds in the extra time it takes to walk to the nearest form of transportation.