John Kerry has decided to do the honorable thing and concede the election. He did it without much delay and well before continuing to hold out would have made him petty and/or childish. He also avoided the sore loser label, though that may not matter. Traditionally the Democratic party tends to not be very helpful in future campaigns to a guy that's lost once. Far more important, I think, is that this eliminates the possibility of dragging Edwards down as well.
This decision is the right thing to do for the country, for his party, and for his running mate. I don't like the man, but he is going out with honor. Unlike someone else I could mention, to say nothing of his supporters.