1) Obama is actually spending time jaunting around the state. Obama doesn't need Pennsylvania to get the nomination, and he hasn't been expected to get it. Clinton could be more efficiently stopped in later states if he would let PA slide. Campaigning here is an aggressive move.
Against all logic, he actually stopped in a restaurant in Mifflin County near my hometown of Lewistown. Mifflin is very small, very Republican, and very white. On the flip side, the Democrats here aren't under the thumbs of the Philly or Pittsburgh political machines.
2) Sen. Bob Casey Jr., the pinnacle of spineless political weather vanes, has endorsed Obama.
Polls? Eh... Obama has to make up no less than ten points... but I think somebody thinks he has a shot.
EDIT: The latest Rasmussen poll from 3/31 has Obama down by five, and HRC under the magical 50% mark. For what it's worth, I tend to have greater faith in Rasmussen than many other polls.
EDIT 2 : (4/02/08) I don't believe the PPP poll from 04/01 showing Obama ahead by 2. Besides the fact that I've never heard of them before, (1) They're partisan, which is a red flag, (2) They aren't based in the DC area, nor in PA, (3) Their previous poll from as recent as 3/16 had the spread at Clinton +26, which was the largest measured spread going back to the beginning of December where Quinnipiac had the spread at Clinton +28.