The registration-surge story isn't exactly new, but the AP has a nice rundown:

In states where registration is recorded by party, including eight key states that could decide the election, voters have signed up Democratic in the past six months by a margin of nearly 4-to-1. ...

Historically, voter turnout among new registrants has been low. And while candidates have months to run registration drives, they have only a tiny window - several days during early balloting, just hours on Election Day - to get out the vote.

Still, an Associated Press analysis of registration data found that if the millions of newly registered voters turn out at the same rate as in 2004 and cast ballots with their declared party of choice, Obama could have the votes he needs to wrest several battleground states away from the Republican Party and its nominee, Sen. John McCain.

Obama could hold Pennsylvania and New Hampshire, won by Democrat John Kerry four years ago, and go on to pick up three states won by President Bush: Colorado, Nevada and New Mexico. He could also narrow the gap in Iowa, as well as in both Florida and North Carolina: two big Southern states worth 42 of the 270 electoral votes needed to win the White House.

A win for Obama in only a few of those eight states could doom McCain's chances. A victory in all could turn the election into a rout.