Polls show Obama increasing his lead in the 08 elections but still not the runaway that many pundits believe the Democrats should be delivering. Toss away those numbers anyway because it's likely this election comes down to two factors which aren't properly captured in any poll: cell phones and racists.
The Pew Research Center recently updated their findings re: the political leanings of "cell phone only" Americans and found"the cell-only respondents were significantly more supportive of Obama (by 10-to-15 percentage points) than respondents in the landline sample. For example, in the September survey Obama led McCain by a 55%-to-36% margin among cell only voters, but the candidates were tied at 45% in the landline sample."
Since most polls use landline samples they could be suppressing an additional few points of Obama support but only if these mostly under age 30 demographic turnout - they are also less likely to vote than landliners.
However this tech-youth bump could be drowned out many times over by closet racism. The Bradley Effect refers to the tendency for certain voters to express support for black candidates in polling, only to not show up on election day or get into the voting booth and pick the white guy.