At that price tag, candidates will need to raise about $10 million a month just to reach the starting gate, and Romney supporters are depending on a cutting-edge fund-raising Web system to do it.

Supporters of Romney, who plans to formalize his race for the Republican nomination in the next few weeks, can become the equivalent of the 2004 Bush-Cheney campaign's Pioneers and Rangers while sitting on the couch with a laptop.

When they log onto QuickComMITT, fundraising volunteers will use a password from the campaign. They will enter information about each person they call, down to whether they couldn't reach them or left a message. The system supercedes spreadsheets of past campaign and the tracking numbers that the Bush-Cheney used to credit supporters for money they had raised.

If the prospective donor wants to make a contribution, the credit card information is processed from the same screen, making the job of raising money for Romney as easy "as buying something from eBay or booking an airline ticket online," according to the instructions for users.

With the major candidates in both parties building huge staffs and opening lavish headquarters months ahead of campaigns past, the pressure is on to raise huge amounts of money at a furious pace. The campaigns have the luxury of raising money online but also face huge expenses for maintaining a constant and sophisticated Web presence to keep supporters engaged, without being able to shave any of the traditional costs like field offices and TV ads.

"We're entering into a new world of presidential fund-raising," said Michael E. Toner III, a commissioner of the Federal Election Commission.

Sen. Hillary Rodham Clinton, D-N.Y., upped the ante when she announced her candidacy by declaring that she was raising money for the primary and general campaigns simultaneously. That means she won't take federal funds for the fall campaign -- the first time a candidate has done that since the new campaign finance system was set up after Watergate.

The practical consequence is that she might be able to spend as much as $250 million in the fall versus the $80 million she would have gotten from the government, making it a virtual certainty that the Republican nominee will do the same, according to party strategists.

Toner, the FEC commissioner, said $100 million in 2007 has become "essentially an entry fee" for the closely spaced primaries and caucuses at the start of 2008.

`People who could give $2,000 in 2004 can give $2,300 for the 2008 primaries, because the campaign finance limits are now indexed for inflation. And they can give $2,300 for the general election.

So someone who was hit up for $2,000 just three years ago might well be asked for $4,600 this time. The Hillary for President Web site already does that explicitly, inviting online contributions ranging from $25 to $4,600. Other sites in both parties top out at $2,300 but leave a space for "other."

Toner said that with donors able to give twice as much at a time, top candidates will be able to raise as much as $9 million in a single evening. The first significant benchmark will be the federal filings for the amount raised through the first quarter, which will become public on April 15. Political aficionados will spend Tax Day poring over a lot more than their IRS returns: Long before the voters of New Hampshire and Iowa have their say, loyal donors in the two parties will help winnow the fields.

So if you've been a big giver in the past, your phone is already ringing with invitations and solicitations.

"The low-hanging fruit is being shaken out of the trees now," said a Bush supporter who was a Ranger, meaning he raised at least $200,000 for the re-election campaign. "People are already starting to get worn out of getting phone calls."

People help raise these gargantuan sums because of access to the candidate and top aides, status with their business and social peers, and excitement about participating in such a vast operation. Past givers are listed in federal disclosure records, so all the campaigns have their names.

But it takes an awful lot of $2,300 checks to add up to $100 million. What the campaigns really need and value are the bundlers -- people like Pioneers and Rangers with many well-heeled friends and business associates who will tell two friends, who will tell two friends, and so on, and so on. Several of the campaigns are getting people started by asking them to pledge to raise at least $25,000.

"It's multilevel marketing," said an experienced Republican fundraiser with contacts in all the campaigns. "Some people will get into it and get real excited and they'll raise a lot more than $25,000 -- they'll raise 100 and others will only raise 10. But you've just got to get the bodies." President Bush has raised more money than any politician in history. So his system has been deconstructed by fundraisers on both sides, and several of the campaigns are blatantly copying some of his strategies. As first reported in the New York Daily News by Ben Smith, now with The Politico, former New York Mayor Rudy Giuliani has created a Bush-Ranger knockoff using a baseball motif, with a descending structure of Team Captains, MVPs, All Stars and Sluggers.