When Johnny Comes Home From War

I have been to all the antiwar marches since 2002 and nothing meant more to me (other than the wonderful support from thousands of people against the Bush regime) than the man who sang "When Johnny Comes Home From War" at the Civic Center after the March 19th march. Does anyone know who he is or where he is playing Monday night in San Francisco? I think he said it was on Valencia Street. I would like to go see him. Please help.