De VCA (Vereniging Constructief Audio) is a Dutch association of members witch are professional and dedicated to sound on film.
STEIM (the Studio for Electro-Instrumental Music) is a independent electronic music centre for live-performances. They support developing, have lots of performances, workshops and Resident projects.
School of Sound has master-classes and a wide range of good articles about creative use of sound with media an art.
Freesound.org is a open source sound database with high and low quality sounds where you are able to download all for free.
Stichting Geluidhinder is a association that has the goal to reduce sound nuisance (noise) in the Netherlands as much as possible.
Filmsound.org has lots of good articles, interviews and books about sound design.
On New American Radio you can listen to a lot of American sound art from 1987 till 1998.
Aafke Beernink, director of photography.