This is by no means a complete list. There is so much more on the internet these days, but this will give those of you a good start who are interested in acoustic ecology, soundscape studies, soundwalks and other forms of environmental listening. It will lead you to more links, open more sonic doors. I will add on as I remember or run across further relevant links.

Sonic Research Studio, Simon Fraser University:
World Soundscape Project (WSP):
World Forum for Acoustic Ecology (WFAE):
Soundscape - The Journal for Acoustic Ecology:
The Centre for Deep Listening:
Walking Festival of Sound:
Wetland Project:
SOUNDSCAPE EXPLORATIONS, Dedicated to Internet videos related to the field of acoustic ecology: