Rasmussen has just posted his most recent Pennsylvania poll, which has Obama widening his lead ever so slightly, to 46-42 (45-43, 5/21/08).
Interestingly
Obama’s gains have come primarily among men—Obama now leads by eight among males. Last month the candidates were essentially even.
1000 LV, +/- 3%, 6/22/08.
Rasmussen has shown a gradual improvement in Obama's support against McCain, and he is improving his support among the state's Democrats, from 63% in the last poll to 69% in the current poll. Clearly, he still has room to improve here among the famous "hard working white voters" that supported Hillary Clinton, and there is no question that that is why she will be campaigning with him in the Keystone state.
Rasmussen has PA slightly closer than some of the other polls that have come out lately, but I think that it shows that Obama has a small but not negligible lead. PA is not a sure thing, but it will likely not be the "tipping" state. That is to say, if Obama is winning the other battleground states he needs to win - OH, MI, CO - then PA will already be in his column.
UpdateJust for reference here are the three most recent other polls from PA via TPM Electon Central:
June 18 Quinnipiac Obama (D) 52%, McCain (R) 40%
May 22 Quinnipiac Obama (D) 46%, McCain (R) 40%
May 20 SurveyUSA Obama (D) 48%, McCain (R) 40%
-- Stu