'This Is As Real As It Gets'

In Internet forums, supporters of Zarqawi pledged their allegiance to his successor, whomever that may be. There is no doubt terror attacks against U.S. troops will go on — and with Zarqawi's weapon of choice, the roadside bomb.

Even today, reports CBS News correspondent Jim Acosta, U.S. soldiers are training for the next attack.

Today troops are conducting what the army considers its most critical training exercise: an American convoy comes under attack in an Iraqi village. Homemade bombs explode and gunfire erupts — all set in motion by an IED, or improvised explosive device. The soldiers have to react.

The army gives this mock battle, staged at Ft. Polk in Louisiana, a gritty realistic edge — from hiring Iraqi-Americans to play panicking residents covered in fake blood — and a barrage of pyrotechnics.

The IED has changed the face of urban warfare, so much that the army now exposes nearly every soldier — even those on their second deployment — to this situational training.

IEDs are now the No. 1 cause of causalities in Iraq. Of the almost 2,500 soldiers killed in this war, about one-third were the result of these improvised explosives.

"They said it was going to be somewhat real," says Staff Sgt. William Payne. "I took it for granted and didn't think it would be, and this is as real as it gets, right here."

Payne knows full well the power of these hidden bombs. In Iraq, he earned the Silver Star by pulling wounded soldiers out of an armored vehicle that was blown up by an IED two years ago. When we met Sgt. Payne, he had just gotten word that Abu Musab al Zarqawi was dead.

"Probably the best news I've heard all year so far," he said.

But these soldiers know Zarqawi's death doesn't mean the end of homemade bombs. This training might mean the difference between life and death.

Brig. Gen. Mike Barbero is confident this IED training will save lives. "We want our soldier's worst day to be here rather than in Baghdad," he says. "We want them to experience an IED, an RPG, a small arms engagement, a mortar attack here."

The training at Ft. Polk is so well respected that the army is planning to export this exercise to military installations across the country.