Nate Silver's latest update addresses mixed signals within the polling:
Mr. Obama’s swing state polls are consistent with the hypothesis that he holds some sort of Electoral College advantage, but they are also consistent with the hypothesis that the national polls have the race slightly wrong. If you start out with the premise that the national polls are unimpeachably precise, then you might not give much weight to this hypothesis. But they are not all that precise as a matter of either theory or practice. The opposite hypothesis — that the state polls are overestimating Mr. Obama’s standing — is also a valid one to consider.
In Ohio, for example, a new survey released on Monday morning by CBS News and Quinnipiac University shows Obama holding a lead of 5 percentage points over Romney (50 to 45 percent). That result represents a net 5-point gain for Romney since the previous Quinnipiac survey before the two presidential debates that showed Obama leading by 10 points (53 to 43 percent).
Obama's Ohio margin was much closer, however, on several automated telephone surveys conducted in the past week, polls that are banned by federal law from dialing cell phones. According to a recent government survey, more than half of the adults in Ohio either have only a mobile phone (33 percent) or use their mobile phone to answer most of their calls (18 percent). A live interviewer poll conducted by Fox News last week that sampled both landline and mobile phones gave Obama a 3-percentage point edge in Ohio (46 to 43 percent).
Earlier analysis of swing-state polls here.