US:  (2005) - "39 percent of U.S. citizens believe the situation in Iraq was worth going to war over"
Coalition of the Willing:  - To much to quote, links to newspaper articles writing about the studies.
Coalition of the Willing:  (2005) - "Overall, 70 percent of respondents said they were opposed to their countries contributing troops to the operation. In no country -- including those, like Poland, that are in fact contributing troops in Iraq -- did either a majority or plurality of respondents say they thought their country should contribute troops."
Britain:  (2005) - "The poll showed that fewer than 29 percent now believe that thewar was the right thing to do, compared to 53 percent who think itwas wrong."