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.
New York Times
New York Times: Sept. 11: One Year Later
The New York Times Learning Network provides a variety of archived news articles, lesson plans, and resources concerning the issues and events that surfaced from the September 11, 2001 attacks.