The History and influence of A. Wallace Rimington's Colour Organ are discussed and debated in these articles about its influence and importance in the UK.
This is an older article (Animation World Magazine, 1997) that details the long history of "color music" (visual music) from its ancient origins into the modern use of movies to create it.
This paper by Robert Emmett Mueller explains how to create "a video color music that can be scored like music and played on a standard electronic keyboard." (in .pdf).
Nature is running an article on Physicist Damian Zanette (of the Balseiro Institute in Bariloche, Argentina) who has done research to compare tonal and atonal musical structures for their simularity to language.
