A highly organized international group of hackers has launched an online campaign against the Church of Scientology.

They have successfully carried out a “denial of service” attack on the organization’s international Web site, causing it to crash. And they have engaged in a sustained campaign of “Google bombing”–manipulating the way the Google search engine works–to ensure that the Church of Scientology is returned as the first hit whenever anyone enters the search “dangerous cult.”

The decision of hackers to target the self-styled church–dismissed by many as an extremely dangerous cult, and banned in several European countries as a “criminal enterprise”–is believed to have stemmed from YouTube’s decision to remove a video from the site showing Tom Cruise hailing Scientology as “a blast.”

The hackers allege that YouTube acted after a campaign of intimidation by Scientologists.

A worldwide day of “direct action” against the Church of Scientology is planned for next Sunday, to voice concerns about its growing power and economic muscle.

Last week the actress Nancy Cartwright, the voice of Bart Simpson, became the latest Hollywood star to fall prey to the Church of Scientology and handed over $10 million to the organization.

You can still see parts of the Tom Cruise clip here in this campaign spoof.