If i was Saddam what i would do is this...
Send in a load of people with supplies of anthrax hidden in their pockets. It doesn't smell and will be deadly.
Send in a load more suicide bombers, a lot of people hate America.
Or I would do this...
Get a Nuclear Warhead (just the warhead) and put it in a van. To let you know, a warhead (and only the warhead) will fit in the boot of the car and isn't very heavy. A man could pick it up without straining himself too much. Then i would put that in the back of a 60' articulated lorry. I would cover the rest of the lorry with things like cat food, or flour sacks.
Then, nobody would find it at customs (especially if the lorry said 'Tesco' on the side or something. I would drive it to the middle of New York. Then i would detonate it.
At EXACTLY the same time. I would detonate similar lorries in Washington DC and about 10 major cities.
Brilliant isn't it?