Perhaps you've become aware of the various on-line markets that now exist for "futures" trading on every proposition under the sun, including election outcomes. Investment speculators in the highly respected Iowa Electronic Markets, almost never wrong, are currently favoring a Democratic House takeover 60-40.
Here's another one I've discovered. I can't vouch for its track record, but here's the current betting on Republican presidential nominees in 2008 -- Huck trails, in order, McCain, Giuliani, Romney and ?!? Allen. We'd definitely take The Huckster over Macaca, if that was the choice.
The Iowa market is trading in wagers on which party will take the presidency in 2008, not individual candidates. In most recent trading, Dems are favored.