This just posted to the IP List, presumably from MoveOn.org. I cannot vouch for the accuracy of it but it is troublingon the face of it:

This just in: Television ads to be run during this year's Super Bowl will
include messages from beer companies, tobacco companies, and George W.
Bush's re-election campaign, but will NOT include an ad from an
organization which opposes Bush's re-election. Ironically, the ad, which
criticises Bush's domestic economic policies, echoes the concerns of many
fiscal conservatives on both sides of the aisle.

This is the second recent incident in which CBS -- which will benefit from
a rider attached at the Administration's behest to just-passed budget
legislation allowing greater concentration of media ownership -- has
repressed content which might displease supporters of the current
administration. (In November of 2003, the network refused to run a movie
which, some say, contained unflattering portayals of former Republican
president Ronald Reagan.)

For more information on this unexpected move (which, frankly, should very
troubling to all of us regardless of political affiliation), see:

http://www.moveon.org/news/2278.html
http://www.mediareform.net/media/
http://sg.biz.yahoo.com/040120/15/3hem8.html