A CBS News/Knowledge Networks poll taken immediately following the debate shows uncommitted voters who watched the veep debate believed Democratic vice presidential nominee Joe Biden did the best job by a margin of more than 2 to 1. The poll (PDF here) also found,

Forty-six percent of these uncommitted viewers said Biden won the debate Thursday night, while 21 percent said Palin won. Thirty-three percent thought it was a tie…Palin’s debate performance improved uncommitted voters’ perceptions of her overall, and on a number of specific measures. But uncommitted voters still have doubts about her ability to assume the presidency if necessary and she lags behind Biden on her knowledge and preparedness for the job….Although Palin made some gains on perceptions that she could serve as president if needed, she rose just nine points on that measure after the debate, to 44 percent. In contrast, almost all uncommitted voters think Biden would be an effective president.

While 71 percent of the CBS respondents remained uncommitted after the debate, 18 percent said they would now vote for Obama, while 10 percent said they would vote for McCain.
A CNN/Opinion Research Corp. poll of ‘people who watched the vice presidential debate’ indicates that 51 percent of those polled thought Biden did the best job, while 36 percent thought Palin did better. The poll also found,

On the question of the candidates’ qualifications to assume the presidency, 87 percent of those polled said Biden is qualified and 42 percent said Palin is qualified…The candidates sparred over which team would be the better agent of change, and Biden came out on top of that debate, with 53 percent of those polled giving the nod to the Delaware senator while 42 percent said Palin was more likely to bring change.

The CNN poll also indicates Palin made some gains:

…Respondents said the folksy Palin was more likable, scoring 54 percent to Biden’s 36 percent…84 percent of the people polled said Palin did a better job than they expected, while 64 percent said Biden also exceeded expectations.

Both polls show it was a very good night for the Democratic ticket. While both candidates increased their stature with voters and there were no major blunders or gaffes, most respondents clearly saw Biden as the best prepared.