In some aspects, yes, most of the media weren't giving the opposition to the war any credence.  The McClatchy Newspaper Group did have reports that contrasted the official line about Iraq being linked with al-Qaeda, but that get a lot of attention.  Many people in the news media were basically cheerleaders - we'd been attacked and Saddam Hussein was a bad man who hated America.  Since these are two different and unrelated statements, the Bush Administration did much to connect the two.  Much of the media paid little attention to the people protesting our going into Iraq prior to the war.  It didn't take someone with a lot of foreign policy experience to realize that there wasn't a tie between Hussein and al-Qaeda.  The Bush administration took advantage of the post 9/11 sentiments of most Americans, cherry-picking intelligence, and the claims that it would take very little time to overrun the Iraqi army (plus all those flowers that the Iraqis were supposed to throw at our troops).

The lesson that media should learn from the run-up to Iraq is that they need to be skeptical and to check with multiple sources.  If the media acts like the majority of reporters did during the run-up to Iraq, we will once again, act impulsively.