The two following websites centralize the addresses of a large number of other sites concerning the media.

Search by site, by name, by city, by country and by language.
http://www.thepaperboy.com
 

American newspapers and periodicals online

The Atlantic Monthly: http://theatlantic.com

The Boston Globe: http://boston.com

The Chicago Sun Times: http://www.suntimes.com

The Christian Science Monitor: http://www.csmonitor.com (very useful: archives since 1980)

The Los Angeles Times: http://www.latimes.com

The Miami Herald: http://www.miamiherald.com (archives from 1982, but not free, from $1 to $1.95 per article!)

The New York Times: http://www.nytimes.com

& : http://www.sfgate.com (the Examiner has archives since 1985) 

The St Louis Post Dispatch: http://www.postnet.com

The Wall Street Journal: http://wsj.com

The Washington Post: http://www.washingtonpost.com

...and, last by not least (for those who prefer "Macnews")
USA Today: http://usatoday.com
 

All-news TV channels:

MSNBC: http://www.msnbc.com

CNN: http:/cnn.com