Be cool, tell the truth and don't look like a terrorist and they'll let you go after 30 seconds. Be a smart-butt and you'll end up having a full body cavity search. <img src="http://www.catsailor.com/forums/images/graemlins/ooo.gif" alt="" />
Todd....you're screwed.
And don't tell them you have a case of Coke in the back either...being from the South, my dad made that mistake once during a trip to the falls (where "Coke" is the generic term for "pop" or "soda")....Sir, please step out of the car.