At Daily Kos, DemfromCt provides good analysis on the latest polling:

Andy Kohut of The Pew Research Center was interviewed on NPR about the recent Pew Poll. He noted that while the voter sentiment hasn't changed, what has changed is Republicans are more energized than they were. The poll was adjusted to reflect that, and there we have the explanation for the poll tightening. Subgroups who have a Dem lead (but not as much as before) include women and independents. The slew of polls we covered yesterday looked at those subgroups as well.

. . . It's not that all of a sudden Bush and Iraq became popular on Friday. What happened over the weekend is interviews suggested that as unhappy as Republican voters are, they'll hold their nose and vote for the GOP. To that extent, the GOP "play to the base" campaign worked as designed.

The importance of likely voter models therefore should be appreciated. Gallup's been doing theirs for a long time, yet in a wave election, the sentiment for change can be underestimated (by definition, the LV model isn't based on changing from the past). Frank Newport thinks it looks like 1994, and the difference is strong enough to take the House.

The dynamics of the race have not changed but the GOP has successfully energized its base. Who turns out will determine the size of the wave on Tuesday.