Of all the weapons used in the Iraq war, the one that  will be remembered most vividly will be the IED (Improvised Explosive Device). Why? For one thing, the number of American casualties it caused. So far, about 47 percent of all American wounded were hit by IEDs, and some 37 percent dead as well. While the new body armor made the infantry less vulnerable, armored vehicles did not do as much for the combat support troops who get hit by most of the IEDs. 

But at the same time, IEDs are not likely to be seen in other wars. Thats because of some unique circumstances in Iraq. The main one was the presence of so much unguarded explosives. Saddam had bought enormous quantities of artillery shells and bombs during his 1980s war with Iran. When that war ended, Iraq found itself with thousands of tons of unused munitions. Saddams secret weapon in getting the Iranians to agree to a truce, was his heavy use of artillery. The Russians were eager to sell Saddam all the ammo he wanted, at cheap prices as well. This was because the Russians maintained huge stocks of artillery ammo, and did not use the older stuff up for training (as was the case in the West). So the shells just sat there until they got too unstable to use, or the Russians found someone to sell it to. Saddam was their man, and the 1991 war over Kuwait used up very little of this leftover ammo. Not much got used during the 2003 war either. American troops moved too fast for the Iraqi artillery to get into action much at all. So when the invasion was over, hundreds of ammo dumps in Iraq were suddenly unguarded. Despite all the oil money (which Saddam reserved for himself and his cronies), most Iraqis were poor. With Saddams thugs gone, for the moment, looting became a form of payback for decades of deprivation. Hauling off 90 pound artillery shells (to be broken open to separate the explosives from the scrap metal) was a popular, lucrative, although dangerous, activity for most of 2003. Suddenly there were lots of explosives for sale, cheap. There were also thousands of artillery and mortar shells that had not been busted open yet, when the Baath Party and al Qaeda decided to stage a campaign of terror against the Shia Arabs, Kurds, and anyone who was helping them (the coalition.) Baath had lots of cash, and there were lots of shells available cheap. This is not a normal situation in most of the world. Without lots of cheap, and easily available, explosives, you cant have a lot of IEDs going off. 

Moreover, the United States is spending billions of dollars to develop new ways to find or disable IEDs. So the next time someone tries to use IEDs as their principal weapon, they will find, as the Iraqi terrorists have found, that over 90 percent of their IEDs will be detected, destroyed or otherwise wasted before they get a chance to hurt anyone. Well, someone will get hurt anyway, mostly the people building the IEDs. Iraqs anti-government forces had lots of people expert at working with explosives. Saddam had thousands of his loyal followers trained in these deadly arts, and many were available for hire after Saddam was out of power and no longer meeting his payroll. Less expert bomb makers tend to blow themselves up. This was seen happening with increasing frequency in Israel last year, after Israel identified and killed or captured most of the Palestinian terrorist bomb makers. The same thing is happening with increasing frequency in Iraq, as expert bomb makers are taken out. And the same thing will happen in any part of the world where there are many guys who want to build IEDs, but dont have the skills to do it and survive the process. 

That said, the two year battle of wits between the terrorist bomb makers, and their American targets, has been well documented by both sides. The Internet is filling up with more and more details of how Iraqi terrorists build IEDs. Most of this stuff is in Arabic, and is somewhat disorganized. But theres lots of practical advice there, for anyone with access to lots of explosives.