Terrorism is just a click away. While Osama bin Laden's shadowy al-Qaeda organization has taken pains to conceal itself and its activities, many other terrorist groups broadcast their messages for all to see on the Internet.

On these Web sites, terrorist organizations comment on current events, denounce their enemies and even attract donations and new members.

"As time moves on, technology presents new opportunities for terrorists and new challenges for law enforcement. It's the nature of the world we live in," notes Edward Turzanski, a terrorism expert from La Salle University.

While authorities say they keep close watch on these sites, they have little power over them. Most of the Web pages are housed overseas, well beyond the reach of law enforcement.

And those sites hosted by American Internet service providers are protected by free speech laws.

The homepage of Hizbollah, a Lebanese terrorist group linked to many bombings in Israel, has pictures showing the organization's leader holding an assault rifle and members grouped around a tank. While the site is primarily devoted to propaganda, it is also candid about the less savory aspects of the organization.

"Hizbollah also used one of its own special types of resistance against the Zionist enemy that is the suicide attacks," notes an introductory statement about the organization's past.

Hamas, another terrorist group dedicated to the Palestinian cause, maintained a site until recently that showed graphic pictures of Palestinian children killed in the recent intifada. The group also has used the site to announce responsibility for terrorist attacks against Israel.

But using the Internet isn't limited to Middle Eastern terrorists. The Tamil Tigers, an armed group in Sri Lanka devoted to winning a separate state for the island's Tamil population, maintain a Web site where users can read angry denunciations of the ruling government or pore over statistics about the "martyrs" slain in the conflict.

And in Latin America, both Colombia's FARC — a leftist revolutionary group fighting a civil war against the government — and Peru's Tupac Amaru Liberation Front — best known for its affiliation with jailed American activist Lori Berenson — both maintain Web sites.

Azzam Publications' instructions for jihad

While bin Laden's organization has no Web site, he does have online sympathizers. One group of sites, maintained by London-based Azzam Publications, is largely devoted to jihad, or holy war, and currently screams "Urgent Appeal to Defend Afghanistan" across its front page.

One of the Azzam sites has a section that interprets the Koran as claiming that jihad is a responsibility for all Muslims. It then gives detailed instructions on how best to train.

"Military training is an obligation in Islam upon every sane, male, mature Muslim, whether rich or poor, whether studying or working and whether living in a Muslim or non-Muslim country," the site says.

"It is better to go to the gym with another brother if possible, or go at a time when there are as few women as possible," the instructions note. "Public gymnasiums are generally un-Islamic places with loud music and improperly dressed men and women."

Authorities in Britain shut down Azzam in the wake of the September 11 terrorist attacks, but the site was up again this week. The company claims to oppose terrorism and the killing of civilians.

Azzam's site, however, includes the text of pronouncements on jihad made by both bin Laden and Egyptian Sheik Omar Abdur-Rahman, jailed for his role in the 1993 World Trade Center bombing.