iCI - What Sound Does a Color Make? explores the fusion of vision and sound in electronic media, and connects the recent boom of digital audiovisual art to its pre-digital roots by presenting a selection of single-channel videos from the 1970s and ten contemporary works by an internationally diverse group of artists.

Media Art Net» thus aims at establishing an Internet structure that offers highly qualified content by granting free access at the same time
image-sound_relations/
overview_of_media_art/audio/12/

Sound and Vision Programme at Banff - now finished but worthy of a look

http://www.iotacenter.org/
"Visual Music" "Mobilcolor," "Lumia," "Absolute Film," "Video Synthesis" "Abstract Animation"...
...different names for what is really a single genre of art – an art of light

Len Lye

Visual Music surveys the charged and profoundly generative relationship between art and music over the last 100 years

A downloadable version of Gene Youngblood's seminal book Expanded Cinema, complete with introduction by R. Buckminster Fuller

Synesthesia, Multimedia & the Caves of Altamira* - thanks to Kath O'Donnell for link

A Brief History of Synaesthesia and Music

Sons & Lumières
A history of sound in 20th Century art
Four hundred works of art that sum up how the interaction between images and sound developed throughout the 20th Century
A great essay outlining the main themes in the Sons et Lumiers exhibition here:
http://www.artnews.info/news.php?i=225&t=news

Timeline of visual music from http://RhythmicLight.com

Centre for Visual Music Archives