The RAND Continuous 2012 Presidential Election Poll has an interesting methodology.
For months now they have been tracking the preferences of the same set of 3,500 people, where they basically ask each person how likely they are to vote and whom they intend to vote for. The results are calibrated to be consistent with the 2008 results, to try to minimize any systemic bias.
Over the past few days, the spread between Obama and Romney has exceeded the 95% confidence level for the first time. Today, the numbers are 49.29% for Obama and 43.91% for Romney.
Using this ballot lead calculator we can calculate the odds that Obama would win the popular vote if the election were held today.
I'll leave that as an exercise for the reader, but DAMN!
3:59 AM PT: I really recommend that you calculate the results. It takes just a minute and I guarantee you'll be impressed.