Amsterdam by Satellite
A brief overview of diamond centres in the city that welcome visitors.
http://www.amsterdamsat.com/diamonds.html

Frommer's
Contains information about diamond tours in the city.
http://www.frommers.com/destinations/amsterdam/0043021221.html

Visit Amsterdam
Find out more about the diamond trade in Amsterdam and the sightseeing opportunities it affords.
http://www.visitamsterdam.nl/city/highlights/diamonds.html