Howstuffworks.com: How Television Works
Easy-to-read article that describes how television works.
Invention of Television
Tells how Philo Farnsworth created the first image dissector in 1927.
Radio Design Group: How Television Works
Brief introduction to the science behind electronic image transmission, satellite images, and high-definition TV.
The American Experience: Big Dream Small Screen
Reveals the little-known story of the Utah farm boy who, at age 14, came up the idea of television. Includes a timeline of TV milestones. From PBS.