I took a look at the voter/party registration numbers as reported on the web by Pennsylvania's Department of State. In general, a good sign.
Pennsylvania's Unofficial Voter Registration by Party, the past five time periods:
November 2003
Democratic - 3,677,488
Republican - 3,204,440
Total of all parties - 7,710,601
April 2004
Democratic - 3,706,122
Republican - 3,230,496
Total of All Parties - 7,780,582
November 2004
Democratic - 3,985,496
Republican - 3,405,278
Total of all parties - 8,366,663
May 2005
Democratic - 3,836,701
Republican - 3,294,568
Total of all Parties - 8,065,536
November 2005
Democratic - 3,841,429
Republican - 3,292,656
Total of All Parties - 8,073,337
It looks like slow and incremental but steady growth for the Democrats. From November 2003 to November 2005, it has gone from a 473K Democratic registration advantage to a 548K Democratic registration advantage.