Howard Dean's (search) Democratic presidential campaign raised an estimated $500,000 at more than 1,400 house parties across the country in a drive to swell his thriving campaign account.

Campaign aides said Wednesday that an estimated 22,000 people attended the parties, and an additional 1,675 people dialed in to hear Dean's conference call to the events. By midmorning, the Dean campaign had raised $14.7 million in the final quarter of the year.

Dean spoke by cell phone Tuesday night while en route from South Carolina to Vermont. He was joined on the call by former Vice President Al Gore (search) and his wife, Tipper, who introduced the Democratic front-runner.

Dean aides said the 13 house parties in Iowa were a crucial organizational tool in preparing for the state's Jan. 19 leadoff caucuses. In New Hampshire, the site of the nation's first primary, 11 parties were planned.

"Basically, the caucuses are local neighborhood meetings," Iowa campaign manager Jeani Murray said. "These house parties are just one more way for people to talk at the local level."

Dean's campaign announced Monday that he had raised $14 million in the last quarter, far ahead of any of his Democratic rivals. The campaign hoped to send the quarter's total to $14.8 million with the house parties.

While Dean has outpaced his fellow Democrats, he's raised less than a third of what President Bush has generated.

A key part of Dean's Internet-driven campaign has been to get backers involved in the campaign by holding monthly meetings, training sessions and community projects.

Murray said that's crucial for Iowa precinct caucuses (search), which are far more complex than a traditional primary election. At those caucuses, backers spend time arguing politics with friends and neighbors before publicly declaring their allegiance to a candidate.

That requires activists to develop a higher level of commitment to a candidate, and one way of building that commitment is to get activists involved in the campaign through various activities, Murray said.