Just on a purely math / statistical point of view and not involving any political banter, it looks like Barack Obama will win the U.S. Democratic nomination, barring some giant shift in the landscape. I'm pointing this out because it's largely ignored by the mainstream news, I suppose they're more interested in making it seem like a dragged out fight even if this conclusion is probable.

CNN has an easy delegate calculator chart that makes it fairly obvious, of the remaining delegates:

Clinton needs 62% to claim the nomination.

Obama needs 44% to claim the nomination.

Obama doesn't need to win states outright, he just needs to fall within that margin, including the remaining Superdelegates.

Clinton won today in Pennsylvania, but not by a wide enough margin to make a serious dent in the seats Obama has already won. By most accounts, it was her strongest state of those remaining and 55% just isn't enough. If she continued with exactly those numbers (which seems unlikely) she still wouldn't stop Obama from going over the top.

Politically of course, it's presumptuous to point this out.