NASA
Nasa: Project Skylab
This site has links to many resources about Project Skylab. Detailed information, articles, videos, and images are available here.
NASA
Kennedy Space Center: Skylab: America's First Space Station
Here you can read about the history and goals for the Skylab mission.
NASA
Kennedy Space Center: The Flights: Skylab
Here you can find information about each of the four Skylab missions from 1973-74.