This stuff makes a nice conspiracy theory, but that's about all. If Obama does not win Pennsylvania you will be crying "election fraud", I'm sure. Problem is, no one has actually been able to demonstrate an actual case of voter fraud. The left (why is always from the left?) has made a lot of noise, but I have yet to see anything that's any more than a conspiracy theory along the lines of, "The results aren't what we wanted so the election must have been rigged."
You may recall that several major news organizations examined the "hanging chad" ballots in Florida and eventually concluded that the certified results were basically correct. (It may have meant that many of the voters were basically incompetent or could not deal with the ballots, but there was no election fraud.) Of course that was not a big story, so the media largely ignored it.
Pretty much the same thing happened in Ohio in '04. Lots of noise from the left, and plenty of conspiracy theories, but no facts. Plenty of wishful thinking, but no facts. Sheesh.
Then there was an ACTUAL case of apparent election fraud in Washington state 2 years ago. But since it was perpetrated by the Democrats, I guess that wasn't newsworthy either.
Oh, well.