From Rasmussen:

Election 2008: Clinton Ties Giuliani 45% to 45% In the race for the presidency, Senator Hillary Clinton (D) and former New York Mayor Rudy Giuliani (R) are now tied 45% to 45%. That’s little changed from a month ago when Giuliani enjoyed a nominal edge, 48% to 47%. The new national telephone survey also found Clinton leading Republican Senator John McCain by four percentage points, 48% to 44%. A month ago, Clinton was up by just a single point over McCain, 47% to 46%.

The poll was taken before the debate though. Would be curious to see a poll after the debate and after Fred Thompson tonight, which sounds like it will be well-covered.

UPDATE: Reader makes an excellent point:

If the question is Rudy vsHillary, then the debate is irrelevant because:
1. Only serious political geeks are watching or reading about the debate. The average American doesn’t care right now.
2. Even if they did manage to poll a significant number of people who actually saw or heard something about the debate, I find it difficult to believe that Rudy was so bad that a significant number would switch to support Hillary.