Fotonatura is a photoagency specialised in nature photography. The database contains more than 1 million pictures made by the best nature photographers in the world. Fotonatura is associated with "Minden Pictures".
ViaDia is a club of friends of 8 Dutch photographers who all produce Audio Visuals. Some members have their own website:
The Austrian company Stumpfl is market leader in the production of projection screens and equipment and software for producing Audio Visuals, for both professionals and amateurs.
Overige sites
The luminous landscape: Much technical information about digital photography, but also essays about "the art of photography".
DPreview: American site with test reports and discussion forums. Don't take the forums too seriously; often the forums contain a lot of nonsens..
Natuurfotografie startpagina: Starting page for Nature Photography