Walter has been sending me great material documenting his work, as he is a media hound and a lightening rod for anyone interested in the topic.
Here is a radio piece on the BBC from last March. Start at 18:30.
From July 5- July 10, 2007, a Japanese TV crew followed Walter for a piece that ran on July 28, 2007. Walter, who gave me this video and asked me to share it online, says it was viewed by 10 million people.