Poblano's superb 538 offers a sophisticated model of electoral prediction through statistical projection. Rather then emulate that let me offer my own far cruder take on the election that should illustrate my underlying confidence in Obama's odds of winning.
As we've seen, Obama is in a strong position to lay claim to at least 264 electoral votes (the Kerry states + Iowa + New Mexico), leaving him just 6 short of victory. Based upon battleground state polling where Obama and McCain are running neck-and-neck, Obama has basically a 50/50 chance in Ohio, Virginia and Colorado. He needs only one of them to break his way to win the White House.
In probability terms, think of it this way: roll a dice 3 times: if it comes up 4, 5 or 6, Obama wins as he has carried the neccesary state to reach 270 EVs. The reverse is the case for McCain: he needs the dice to come up his way on each and every occasion. (John, naturally, informs me that the odds of rolling a 4,5 or 6 at least once out of three attempts stand at 87.5% whereas the chance of three consecutive 4, 5 or 6 rolls is somewhat harsher at 12.5%.) And this is before we even consider the Yahtzee-like scenarios that include Nevada + Nebraska EV, North Dakota + Montana, North Carolina, Missouri, Indiana, Georgia etc.
All in all, not a bad position to be in prior to: naming your running-mate, having your Convention (in Colorado), facing off in the debates and unleashing your General Election financial and field advantage.