Psychology
General Tutorials in Psychoacustics
Chris Darwin's homepage - Tutorials in auditory perceptionSoftware for Research in Auditory Perception
Praat - The website says "Praat: doing phonetics by computers", but this small software does much more than just phonetics, it's full of goodies for people interestead in different areas of auditory perception. Authors: Paul Boersma and David Weenink. Released under the GNU General Public Licence. See also the Beginner's Guide to PraatCOLEA - A Matlab Software Tool for Speech Analysis
Pyaudiolab - Provides a Matlab-like API for audio input/output (including wav and other file formats) for python.
Digital Signal Processing
The Scientist and Engineer's Guide to Digital Signal ProcessingIntroduction to Sound Processing - book by Davide Rocchesso
Audio Signal Processing Basics with MATLAB code