From CNN.com:
"Did the debate change many minds? Not according to the poll. After the debate, the same percentage of those interviewed -- 54 -- said Bush would be better on Iraq than Kerry.
The story was almost the same on who would be a better commander in chief -- 55 percent said Bush would be better before the debate, 54 percent said so after the debate. Although Kerry made a better impression on some basic measures and may have been successful at re-introducing himself to voters, the poll showed he might not have changed many minds on Iraq and military matters.
"Because the poll talked just to debate watchers, only subsequent surveys will be able to determine whether Kerry gained any votes. Four years ago, a plurality of debate watchers thought Vice President Al Gore, the Democratic nominee, had done a better job than Bush in the first debate. But when the dust settled Bush was the one who picked up a few points in the horse race. Gallup has asked the question about who did a better job in the debate in five previous elections, and in four of them the candidate who 'won' the first debate did not win the election in November."