Hotline/Diageo is out with a new poll of likely caucusgoers in Iowa (Dec 7-12, 569 Dem LV, MoE +/- 4.0%; 446 GOP LV, MoE +/-4.5%) showing Hillary Clinton and Barack Obama in a dead heat, with John Edwards five points back:

Democrats
Obama 27
Clinton 27
Edwards 22
Richardson 8
Biden 5
Undecided 8

Obama leads by just 1.8% in the updated RCP Average for Iowa.

On the Republican side, Huckabee is up 13 points on Romney. And in the important battle for 3rd place, the Hotline/Diageo poll has Rudy running ahead of Fred Thompson:

Republicans
Huckabee 36
Romney 23
Giuliani 12
Thompson 8
McCain 5
Paul 5
Undecided 9

Huckabee leads by 13.6% in the RCP Average for Iowa.

Other notables; 53% of Republicans and 44% of Democrats say there is a chance they will still change their minds about who to support.