ARG, beginning the last day of 2007 and completed yesterday: Huckabee 29, Romney 24, Thompson 13, McCain 11, Giuliani 8, Paul 6.

Looks like a pretty tight screen:

Sample Size: 600 completed telephone interviews among a random sample of likely Republican caucus goers living in Iowa (535 Republicans and 65 no party (independent) voters).
Sample Dates: December 31, 2007-January 2, 2008
Margin of Error: ± 4 percentage points, 95% of the time, on questions where opinion is evenly split.
Incidence of Likely Republican Caucus Participation: 8.6% of Republican and no party voters.