PBS
Pbs: American Roots Music
If teaching a unit about the history of popular music in America, this PBS web site supporting their four-part TV broadcast of a few years ago would make a great resource. Includes lesson plans and oral histories too.
Rock and Roll Hall of Fame
Rock & Roll Hall of Fame: Lead Belly
From Lead Belly's posthumous induction into the Rock and Roll Hall of Fame in 1988. A biography, timeline, audio clips, and the transcript of Pete Seeger's speech inducting Lead Belly into the Hall of Fame.
Wikimedia
Wikipedia: Lead Belly
Biography of influential blues musician Huddie "Lead Belly" Ledbetter.
Encyclopedia Britannica
Encyclopedia Britannica: Leadbelly
This entry from Encyclopedia Britannica features Leadbelly, an American folk-blues singer, songwriter, and guitarist whose ability to perform a vast repertoire of songs, in conjunction with his notoriously violent life, made him a legend.