The technology-themed section of the PBS American Experience archive is the gateway to the transcripts of several great documentaries and includes resource pages for each film. There's a surprising wealth of information—written by recognized historians—and links to some pretty cool primary documents like the entire list of Thomas Edison's U.S. patents.

There's also an "Innovators" section on PBS's "Who Made America" website that features biographical sketches of dozens of American inventors, links to articles their work and context, and a time line laying it all out chronologically.