I think that Kerry won the debate. I thought many times Bush looked foolish in his answers. Either he couldn't find the correct words or he's made dumb faces. Surface level garbage aside, Bush was not good at attacking Kerry.
Bush persistanly said Kerry changes positions because of politics. However, he never gave a solid example. Something the Kerry campaign should focus on is that Kerry has changed positions. That's not due to politics, that is due to new intelligence. When we went to war with Iraq the intelligence was astonishly incorrect. Of course we want to go to war when the CIA is saying Saddam has biological weopons, weopons of mass destruction, and might start a nuclear program. However, once we realized that intelligence was incorrect Kerry changed how he felt about our invasion of Iraq, everyone did - except right wing nut jobs.
One thing I do agree with is that Kerry alluded to the fact that the Bush campaign is trying to make Americans see the situation in Iraq with rose colored glasses.
This website has two great articles written by a soldier and a journalist currently in Iraq which gives you a better idea of the true state of Iraq.