Here is a list of what I could find for mainstream coverage (19.30 Pacific):
ABCnews.com: 2nd headline. Runs a version of AP article which claims a crowd of "thousands."
msnbc.com: Top story. Same AP article, 10's of thousands. Includes an excellent video that lets the people tell their story.
cnn.com: Top story. CNN actually wrote its own article to go with the AP one, asking who will be the leader after this? The same question was asked after April 15, then after July 4th. They don't get it.
Google News: Nothing. Very surprised about this. 5th story on the "US" tab, with the first being coverage of Obama's Minneapolis speech... attended by 15,000.
Yahoo!: Nothing. nada.
Foxnews: 3rd story. Adapted the AP article.
lemonde.fr: 4th headline
aljazeera.com: 2nd headline, runs AP article
nytimes.com: Sidebar near top. They even wrote their own article.
I have been hearing about mainstream media bias. I remember the Million Man March, which may have been smaller than this, was trumped up for weeks before hand and reported live by most major cable news outlets. I can't say if that was the case today, and I'm not sure if any difference is due to news organizations just not being nearly as well-capitalized and relevant as they used to be, or some form of bias. From just these front pages though, it would seem they are reporting the Tea Party movement, or at least begrudgingly channeling AP sources on the matter.