Columbia Journalism Review: "List of Media Owners"

This list may be outdated, but it gives us a general idea as to who owned what in the media.

http://www.cjr.org/tools/owners/

Advance
American Media, Inc.
Belo
Bertelsmann
Cablevision
CanWest Global Communications
Cisneros Group of Companies NEW
Clear Channel Communications
Community Newspaper Holdings, Inc.
Comcast
Copley Press Inc.
Cox Enterprises
Cumulus
Disney
Dow Jones & Company
Emmis Communications Corp.
Entercom Communications
E.W. Scripps
Freedom Communications
Gannett
General Electric
Hachette Filipacchi
Hearst Corporation
Hollinger
Knight Ridder
Landmark Communications
Lee Enterprises
Liberty Group Publishing
Liberty Media Corp.
LIN TV Corp.
McGraw-Hill
Media General
MediaNews Group, Inc.
Meredith
McClatchy Company
Morris Communications Corp.
News Corporation
New York Times Co.
Pearson
Primedia
Pulitzer, Inc.
Reed Elsevier
Sinclair
Sony
Time Warner
Tribune Company
Viacom
Vivendi Universal
Vulcan
Washington Post Co.
Young Broadcasting

Very through. It doesn't look to outdated.