audiovisualizers.com - Excellent history/research/timeline of some of the earliest visualizers and sound/image
machines.
rhythmiclight.com - Great work on outlining the history of light play, from the ancients to the moderns.
materialcinema.org - Site dedicated to the Monadic Institute, researchers on positive uses of sound and image (film/video). It also has an interesting section dedicated to the dementia/side effects of cinema/television.

Projexorcism with his rack at Eyedrum in Atlanta after a spontaneous collaboration with Matterlink and Elmapi
Projexorcism - If vampling had its equivalent in 16mm, this might be how it would look. This insanely explosive performance involves running four dangling 16mm projectors as the sound and celluloid are tweaked till all hell breaks loose.
ninjatune.net - This site has more info on various vamplers on Coldcut's label, especially regarding their Timber project.
retiary.org - One of our mothers of invention: Laurie Speigel of the VAMPIRE project.
bionicdots.com - While dedicated largley to the visual aspect, this group has pushed the live video thing to an extreme, cultivating what they call "Abstract Hyper-Realism" and experimenting with crazy challenging set ups such as working out a seamless 500ft. circular screen event. Their material is both sampled and computer generated.
Andrès Burbano - Columbian documentarian who also explores "algorithmic cinematic narratives" working with non linear deep-transmission experiments in his interdisciplinary collaborative work in digital art. On his site, check out his collaboration with Hernando Barragan, Typovideo, a system of video streaming ASCII.
unitygain.org - Media crossroads, NY style, focusing on live AV performance.
crac.org - Digital arts resource in Sweden, see what government subsidies can do...
Golan Levin - Pioneering veteran engineer and composer "whose work focuses on the design of systems for the creation, manipulation and performance of simultaneous image and sound, as part of a more general inquiry into non-verbal communications protocols in cybernetic systems."
AmoebaTechnology.net - Amoeba is a collective of visual artists and musicians active in NYC and worldwide "engaged in a broad spectrum of activities, including live performances, installations, psychoacoustic research, performing live audiovisuals, producing short videos, films and musical compositions as well as producing and curating events with invited Djs, musicians , installation, multimedia, sound and visual artists". Check out their work with Psychic TV!
roulette.org - Good multimedia space in NY which occasionally mixes it up with vampler type work.
Expanded Cinema - The whole book is online! Youngblood's cinema bible outlines his theories on Synaesthetic cinema, the "Audience and the Myth of Entertainment", "the end of drama", and the attainment of audio-visual nirvana. Read it and don't weep, get to work.
onedotzero.com - English multimedia/digital visual arts festival, encourages exploration and supports artists materially and conceptually.
experimentalTVcenter.org - Residencies, grants, video preservation work, overall a valuable entity, founded in 1971.
improvart.com - NSA = Not Still Art. Since 1995, festival of realtime digital media located in Cherry Valley, NY.