http://www.electoral-vote.com/index.html
Scroll down the page to the final 2000 national poll results. While Gore was just slightly higher in the final popular vote, only 2 polls had Gore ahead, with 2 tied. This suggests to me that however the pollsters were doing things in 2000, they had a sample that was skewed Republican. Perhaps younger voters hang up on pollsters more than older people? With the cell phone factor missing a lot more younger voters than in 2000, this may skew the poll sample even more Republican.