In the last half hour, the Zogby folks have done some correcting to their site and the numbers now make more sense. I think there was a problem where they'd updated some parts of the site and not others, and now they all match up.
Kerry won 252 electoral votes in 2004. He wound up with 251 because one elector didn't cast his ballot properly but that's irrelevant. If Obama starts with the exact same states plus he wins Iowa (7) and Virginia (13), he's at 272 and he gets to live at 1600 Pennsylvania Avenue. There are obviously other scenarios that get him there but right now, McCain has pretty much conceded Iowa, and all the polls seem to have Obama ahead in Virginia by 7-11 points.
Zogby presumes Obama has a lock on all the Kerry states but one. He has New Hampshire (which Kerry carried) in the "probable" column. But he also has New Mexico (which Kerry did not win) as a safe state for Obama. New Hampshire has four electoral votes and New Mexico has five. So that explains why Obama is at 273 in the Zogby poll. Before the update, that wasn't evident.
I still think Zogby is unreliable but in this case, their findings match what almost all the other pollsters are saying. And Mr. Zogby is still contradicting his own polling when he suggests that McCain can win if he sweeps all six states where Obama's lead is within the margin of error. Right now, Zogby has Obama at 286 even if McCain wins all six.