Linkharvest: Are Polls Undercounting Obama Supporters
This study by the Pew Research Center, the answer appears to be "possibly a smidge, but not more than a smidge." In three polls and interviews by PEW conducted from cell phone pools, they found that the variance from the standard landline only polling pool was 2%. That is within the acceptable margin of error. Of note, it was always 2% and always in favor of Obama. OTOH, three polls is a fairly small sample size.
Guess we'll actually have to hold the election after all.