Polls versus markets: which crowd is wiser?

The Electoral Vote Predictor, based on polling data from each state, currently has Kerry winning key swing states like Ohio and Florida to capture the election.
The Iowa Electronic Markets (IEM), cited in a wide range of texts as evidence of the predictive power of free, open, and thus efficient markets (IEF was most recently cited in The Wisdom of Crowds), has Bush ahead as Dubya's shares are outselling Kerry's by a bit ($0.52 for a share of Bush, $0.49 for a share of Kerry at my last check) in the 2004 US Presidential Winner Takes All Market.
Markets have slightly outperformed polls over time, as noted by this study from the IEF (PDF file). This tight and hotly contested election should be a great test to compare these two predictive methods.