Electronic Music: collections, archives, information...

Videotaped interviews, a number of important pioneering voices in electroacoustic music:
http://www.ericchasalow.com/oralhist.html

The Database of Recorded American Music:
http://dram.nyu.edu/dram/

Latin American Electroacoustic music collection:
http://www.fondation-langlois.org/flash/e/index.php?NumPage=542

120 Years of Electronic Music
http://www.obsolete.com/120_years/

Electronic Music Foundation
http://www.emf.org

Medien Kunst Netz:
http://www.medienkunstnetz.de

UbuWeb
http://www.ubu.com

Audiohyperspace
http://www.swr.de/swr2/audiohyperspace/engl_version/index.html

World Forum for Acoustic Ecology
http://interact.uoregon.edu/MediaLit/WFAE/home/index.html

Handbook of acoustic ecology
http://www.sfu.ca/sonic-studio/handbook/

Electro Acoustic Resource Site (EARS)
http://www.ears.dmu.ac.uk/rubriqueGlossary.php3

Physical Attributes of Acoustic Sound
http://www.sfu.ca/sca/Manuals/ZAAPf/p/physical_attributes.html

Sonify.org - interactive sound for the web & wireless
http://www.sonify.org/

Sound effects (FX)
http://www.findsounds.com/   or  
http://www.sounddogs.com/start.asp

Peep (The Network Auralizer)
http://peep.sourceforge.net/intro.html

International Community for Auditory Display
http://www.icad.org/

Collaborative sound database (Creative Commons)
http://freesound.iua.upf.edu/

The History of Crossover Art - Crossing the Borderlines between Image and Sound
http://web.archive.org/web/20030627093609/http://cmt.siba.fi/studies/Courses/2001-2002/_hidden/tutorials/crossover/

Java Boutique - audio applets
http://javaboutique.internet.com/audio/

Sound physics vs. human hearing
http://www.silcom.com/~aludwig/EARS.htm

About decibels, basic
http://science.howstuffworks.com/question124.htm

About decibels, advanced
http://ccrma.stanford.edu/~jos/mdft/Decibels.html
  
History of recorded audio (+ pictures, mp3s...)
http://history.acusd.edu/gen/recording/notes.html

Wikipedia
http://www.wikipedia.org