A few days ago Hillary Clinton had a 12 point lead in Pennsylvania, a key state with 158 delegates. Then another poll showed her lead slipping to 9%, but still a comfortable margin. However the two latest polls show Obama to be in a statistical tie (43.5% each as an average).
The whole Clinton campaign has relied in the last few weeks on getting enough delegates to be close enough to Obama to justify counting the votes from the two state primaries she won which were disqualified. But if Hillary Clinton cannot win Pennsylvania, Obama's lead may actually grow and her chances may well evaporate at this point.
It's all speculation, but I reckon Obama has won it and Hillary needs to go with dignity.