Here is the organizational landscape of the April 15 tea party movement, in a nutshell: three national-level conservative groups, all with slightly different agendas, are guiding it. All are quick to tell you that the movement is a bottom-up affair and that its grassroots cred is real.

They are: FreedomWorks, the conservative action group led by Dick Armey; dontGO, a tech savvy free-market action group that sprung out of last August's oil-drilling debate in the House of Representatives; and Americans for Prosperity, an issue advocacy/activist group based on free market principles. Conservative bloggers, talk show hosts, and other media figures have attached themselves to the movement in peripheral capacities. Armey will appear at a major rally in Atlanta, FreedomWorks said.

All three groups vehemently deny that the movement is a product of AstroTurfing--fake grassroots activism organized from the top down--as some on the left have claimed. They will tell you that citizens-turned-activists, upset with President Obama's economic agenda and the financial bailout, have been calling them, asking for help and how they can organize protests on Wednesday. The movement, they say, is entirely organic: they are mostly providing help and resources to this new class of outraged conservative free-market populists, some of whom are their own members and some of whom are outsiders to politics with whom they've never communicated before--not even on an e-mail list.