De Vlinderstichting – A Dutch organization for butterflies and dragonflies
Waarneming.nl – Web site where you can post and read observations relating to flora and fauna in Holland
Limburgs Landschap – Everything about nature preserves in the Dutch province of Limburg.
Staatsbosbeheer – All the Dutch National Parks and Nature Preserves
Natuurmonumenten – Nature Preserves in Holland, under the management of Natuurmonumenten
IVN – Institute for Nature and Environment Education
HotPixels – Design studio for professional web-sites, located in Hawaii (also not a bad idea)