Mr. Lux said Republicans have been successful for years by "moving money" to groups such as the National Rifle Association and the Christian Coalition.
The Progressive Donor Network's goals also include forming "rapid-response teams" to plant news stories critical of Republicans and the Bush administration. Its leaders cited several negative news stories recently about the collapse of Enron, the Texas-based energy giant with ties to the White House.
Mrs. Boxer said the organization's real value for Democratic candidates could come from its grass-roots efforts.
"They can help get out the vote, organize, register," she said. "Progressives need to have, just as conservatives have, a really good grass-roots network. And I think we've fallen down on that job.
Liberal activist Michael Lux has created the Progressive Donor Network, aimed at steering donors toward several groups, including the National Abortion and Reproductive Rights Action League.
Another prominent Democrat -- Joseph J. Andrew, who joined the law firm of Cadwalader, Wickersham & Taft after chairing the Democratic National Committee last election -- has urged some clients to give generously to the New Democrat Network.
Joe Carmichael, president of the State Association of Democratic Chairs, said he has spoken to veteran political adviser Harold Ickes on the subject and is seeking advice from Steve Rosenthal, political director of the AFL-CIO.