The notion that insurgents (perhaps you would prefer "freedom fighters") in Iraq are resisting the US military is basically absurd. Fewer than 4000 coalition troops have been killed over more than 4 years. That's fewer than a thousand troops per year, out of an occupying force of more than 100,000. Contrast to Vietnam, where more than 50,000 were killed in a 4-year period.
The real secret to the insurgency's "success" is that they don't mind murdering innocents. In fact, if they kill enough innocent Iraqis, they'll probably win. So the real lesson here is not that a determined populace can defeat an armed aggressor. It's that extremist groups using cell phones and the internet to coordinate and armed with relatively modern weaponry can beat the hell out of unarmed civilians living in
clay buildings. So take those IEDs and head down to the local elementary school, should be a real soft target.