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.
Encyclopedia Britannica
Encyclopedia Britannica: Buddy Guy
This entry from Encyclopedia Britannica features Buddy Guy, an American blues musician noted for his slashing electric guitar riffs and passionate vocals.