TalkLeft has a roundup of polls on the eve of the Pennsylvania Democratic primary. Most show a Clinton advantage. According to Drudge, Clinton's own internals seem to put her about 11 points ahead.
UPDATE: Clinton's team is denying the existence of any such internal polls:

"I encourage you to try and get a copy of the poll," Wolfson said, "because no such poll exists." Wolfson called it an "obvious attempt" by someone to boost expectations for Clinton on the eve of the primary vote in the Keystone State.

Meanwhile, the Clinton campaign will try to downplay expectations. And so it goes...