PBS
Pbs Online News Hour: Evening News Tom Brokaw
This site has an interview of Tom Brokaw that investigates the importance and impact of the Evening News shows put on by the big broadcast networks.
Other
Before and After: The New Face of Nightly News
Interesting article follows the return of "hard" news to the 3 evening newscasts from June to October 2001. Includes infographics and source material.