Good read over at Read/Write web and the Software Abstractions Blog. Quick summary.

1. Prediction Markets are a great mechanism to extract knowledge already present within the organization and to make better predictions
2. These markets highlight both the collective wisdom which no one person knows individually, and common knowledge which no one is willing to talk about openly
3. They work properly only when they have an adequate number of knowledgeable participants who work individually
4. Participants must have reasonable incentives (financial or social) to make their efforts worthwhile
5. If the group is large enough, the ratio of experts vs amateurs does not have much impact; often, the real experts are unexpected
6. The results of a Prediction Market are probabilities; they must be confirmed through other, external, means

Loved the idea of tracking team progress against a goal using collective wisdom and predictive markets theory. This should be a feature in all project management software.