"It seems there was a world wide event some time back
where at "X" o'clock local time people were supposed to sing a
song--and keep it going around the world..some peace thing i think..
if we could find this we could use it as a model..i believe there
were giant video screens set up so everyone could experience the
concerts...if they were not able to attend in person.."

upon further investigation
and after polling some others,
I believe this is the event i was
thinking about...it happened last July.

http://www.liveearth.org/

http://www.liveearth.org/event.php

while searching for this is found also
http://www.oneearth.org/