First, he absolutely must be tried by the Iraqis. They suffered the most and they deserve the justice of his trial. Now, that fact being stated, there would definately be a guilty verdict and the death penality would be imposed. The date, however, would be held "open". We make this little deal with this piece of crud: with every piece of information that he gives us (on WMD, where the billions of buck are, his involvement with terrorism, turning in other terrorists, etc) he buys himself another day/days of life. Of course these tidbits of info would have to be validated, and if false the sword drops that day.
I think it's a win/win situation, except for Saddam. When he has outlived his usefulness we look at the Iragi National Congress and say, "He's all your boys"!