The Nets have called Maine for Obama, by 59 - 41. Hillary's fired her campaign manager (probably about a month too late to make a difference.)
Next up, Obama is set to do well in, and possibly sweep, the "Potomac Primary" on Tuesday.
A week after that, Wisconsin - which is a tough call at this point, though a poll on February 7th showed Hillary leading 50-41. My current sense is that this will be a narrow win for Clinton, with the state's delegates more or less evenly split between Clinton and Obama.
Hillary's last chance to lay any plausible claim to being a front runner is on March 4th, when Texas and Ohio vote. If she wins these convincingly, and then wins Pennsylvania in April, she can make a plausible case that she's back in it. If Obama takes one of those, it gets harder for her: if he takes two of the three, it's over for the Clinton campaign.