The creation of AnObamaMinute.com comes after the Illinois senator's campaign announced it raised nearly $40 million in March, nearly double the amount raised by his primary season rival, Sen. Hillary Clinton, D-N.Y., BusinessWeek.com reported.

AnObamaMinute.com is exhorting donors -- who can pre-register -- to log in and make a pledge within 60 seconds at 1 p.m. on Monday, April 21, the day before the Pennsylvania primary. Polls show Obama trailing Clinton in Pennsylvania.

Analysts said the Web site underscores the engagement and enthusiasm that has buoyed Obama's campaign.

"In some ways, the Internet connects Obama supporters better," Larry Sabato, director of the Center for Politics at the University of Virginia, told BusinessWeek.com. "Clinton and McCain supporters are generally older, and this kind of high-speed fund-raising may not exactly be the way they think."

Calling Obama "the greatest fund-raising success in American history," Sabato said AnObamaMinute.com "is another wrinkle, another innovation that confirms the Internet's potential."