More than 250,000 U.S. troops stand at the ready, prepared to defeat Saddam Hussein's army, topple the Iraqi dictator and liberate his people. All they need is for President Bush to say when.

Troops at American military bases in Kuwait and other launchpads listened intently to the president's address Monday night, during which he gave Saddam an ultimatum — get out of Baghdad within 48 hours or face a military attack of a coalition of the willing.

"He [Saddam] better be packing his bags," Sgt. 1st Class Eric Alfred, of Twin Mountain, N.H., said in the Persian Gulf.

"We can't allow Saddam Hussein to continue with his weapons of mass destruction," said Lance Cpl. Michael Clark, 22, of Rosalie, Calif. "We just want to do our job so that we can get back home."

Pentagon officials told Fox they had already gotten a number of anecdotal reports of handfuls of Iraqi troops trying to surrender in the north. Senior Defense officials expect large numbers of defections in the first hours of a war.

Many U.S. troops deployed in the area have been sitting around, not knowing when the United States would act.

"Obviously everyone's going to be nervous, but this is what we are trained to do," one British soldier told Fox News. "We joined the Army for a reason and this is it."

"When Secretary Rumsfeld tells us to go, we're ready to go," Air Force Secretary John Roche told Fox News.

Asked whether U.S. troops would be ready to fight before the 48-hour time limit is up, U.S. Air Force Chief of Staff Gen. John Jumper said: "We're ready to go — we've got the assets, we've got the training, and we're ready. [The troops are] ready to deal with anything they're confronted with."

Central Command Chief Gen. Tommy Franks has assembled about 280,000 troops, including 30,000 from Britain, many of them stationed in Kuwait for a ground invasion. There are also 2,000 Australian troops on the ground in Kuwait.

Altogether, the number of troops is less than half that of the 30-nation coalition that beat Iraqi forces back from Kuwait in the first Gulf War.

Franks was in Kuwait Monday meeting with his troops and the country's leaders after a weekend of visits to talk with leaders in Bahrain and Jordan. On Tuesday, he was back at his headquarters in Qatar, waiting for Bush to make the war call.

Along the Iraqi border with Kuwait, a brigade of the 82nd Airborne Division practiced night parachute jumps.

"We are at the very pinnacle of combat readiness right now to conduct an airborne assault," said 82nd Airborne Div. Cmdr. Maj. Gen. C. Swannack.

Senior U.S. Defense officials said that while U.S., British and Australian troops were the only expected combat forces, other countries have contributed chemical and biological detection teams and follow-on forces, as well as overflight rights, basing and refueling services.

Military action continued to increase near Kuwait's border. Troops on the ground there were issued large quantities of ammunition over the past few days and have moved out of their bases into tactical assembly areas.

"It's extremely important to know that your soldiers will not come upon a situation we have not talked about, not drilled, not practiced," Col. David Perkins of the 3rd Infantry Division told leaders of his 4,000-soldier troop in Kuwait, as about 70 troops armed with tanks moved closer to the Iraqi border.

The main Army forces are the 3rd Infantry Division and the 101st Airborne Division, the Army's only helicopter assault division — both in Kuwait. The 3rd infantry has more than 200 tanks at its disposal. They're supposed to spearhead the drive the military operation to Baghdad.

More than 50,000 U.S. Marines were waiting for orders in northern Kuwait. Some are supposed trek up the western side of the Tigris-Euphrates Delta toward Baghdad, while others will join British troops to capture Basra in the south and the Shatt al-Arab waterway, Iraq's outlet to the Persian Gulf.

Then there's the air assault. More than 10,000 U.S. and British warplanes have been waiting for the go-ahead to drop as many as 3,000 precision-guided bombs and missiles in the first 48 hours of war. The skies in Kuwait were buzzing with attack helicopters, troop transport choppers and anti-tank jets.

The first planes to fly into Iraqi airspace may be the Air Force's stealth jets — the F-117B Nighthawk fighter and the bat-winged B-2 bombers, both of which are invisible to radar. The Nighthawks led the attack on Baghdad in 1991.

On the seas, three U.S. aircraft carrier battle groups are in the Persian Gulf and two more are in the Mediterranean.

There are now 11 Tomahawk missile platforms in the Red Sea — one cruiser, four destroyers and six submarines.

Sailors aboard the USS Truman are also prepared to take out key Iraqi defenses.

"These munitions are used for any target that is being chosen by the pilot," said Lucien Penn, Aviation Petty Officer First Class. "They're laser-guided, so they're extremely accurate, whatever target the pilot chooses. As you can see, the bigger the bomb, the bigger the target."

U.S. soldiers from 31 different Army units were also taking part in a task force that's part of the Free Iraqi Forces training program — the aim of which is to train Iraqi opposition volunteers to assist coalition forces in civil-military operations.

The U.S. assault strategy even extends into orbit.

"We're the No. 1 space-faring nation," Major General Judd Blaisdell, the director of Space Operations and Integration for the Air Force, told reporters in a briefing last week. "It's the ultimate high ground."

About 33,600 military personnel are spread throughout 21 U.S. locations and 15 places around the globe to provide support to troops on the ground. Satellite images provide reconnaissance and can tell troop commanders whether there are enemy forces nearby or whether U.S. targets are in sight.

The Defense Meteorological Satellite Program can tell U.S. forces whether the weather will be appropriate to launch various operations.

A Defense Support Program satellite — a warning satellite — gives a heads-up to commanders of possible incoming missiles. It also gives them impact points and the missiles' points of origin.

Global positioning systems provide the accuracy necessary to deliver precision-guided munitions to avoid collateral damage but still hit targets.

"Here is an opportunity to not only move from day-to-day operations but to continue to make a difference in any battle that we enter," Blaisdell said. "Space over time now has — since Desert Shield, Desert Storm, which was really the coming-out portion of that — has really made a difference."

Fox News' Bret Baier, Greg Kelly, Kelly Wright and The Associated Press contributed to this report.