It was exactly 100 years ago, Christmas Eve 1906, that Reginald Fessenden first transmitted audio, rather than just telegraph sounds, over radio. There is controversy surrounding some of the details of the event, but nevertheless it was a monumental achievement. The transmission was made from Massachusetts, as told in this radio report.
[audio:http://www.dograt.com/Sounds/Wordpress/DEC06/fessenden.mp3]Picking up the story from there, American Radio Works has a 1-hour radio documentary on the history of music on radio, that you can get to by clicking here. If you have trouble listening to it let me know, and I’ll post it here.