Rep. Joe Wilson chose an unconventional venue in which to level an attack on President Obama Wednesday night: a joint session of Congress.

Now Wilson's opponents are counterattacking him in an increasingly popular venue for political mayhem: cyberspace.

Sources close to the South Carolina congressman charge that hackers have blitzed his campaign Web site JoeWilsonforCongress.com with a series of attacks that periodically shut down the page. 

The South Carolina Republican jeered at Obama "You lie!" during his health care reform speech to Congress on Wednesday. Though Wilson's Democratic opponent Rob Miller raised hundreds of thousands of dollars following the outburst, Wilson saw a fundraising windfall of his own, raising $1,000,000 in online campaign contributions since Wednesday night. Now sources familiar with Wilson's campaign say there's a concerted effort by hackers to flood the congressman's Web site and keep him from raising money.

"This is an obvious effort to stifle the congressman's voice for a common-sense approach for health care reform," said a source familiar with Wilson's campaign.

Sources say Wilson's opponents ganged up on the Web site, dispatching thousands of "phantom" computers, infected with malware, to send request after request to Wilson's campaign Web site. Such a barrage of requests overwhelms the site and causes it to crash. A source close to Wilson indicated that hackers took down the campaign Web site for five hours Friday night.

"These tactics create such a huge surge," said a Wilson campaign source. "We've had to fight this off in hand-to-hand combat, blocking this malicious traffic."

In many respects, this is the high-tech version of a politician's opponents driving through a neighborhood and vandalizing campaign signs. In computer-speak, the effort to ping the computer so frequently creates what's called a "denial of service request." That takes the site offline.

"It's like an 'e-warrior' kind of politics," said David Almacy, a senior vice president at Edelman Public Affairs who studies the nexus of technology and government. "There are groups of people who believe that if they can shut down someone's Web site, they hurt their ability to campaign."

Almacy likened the assault on Wilson's Web site to an August effort by hackers to take down the micro-blogging site Twitter and stymie the social-network site Facebook. In that instance, armies of infected computers repeatedly pinged Twitter and Facebook, sometimes millions of times a minute.

The requests to visit the pages eventually overwhelmed the sites because they simply didn't have the bandwidth. Wilson sources suspect the same is true in with these hacks.