Hi, here is my question:
Both my wife and I moved from CA to PA in July 2008, my wife worked in PA and I worked in NY. For convenience, I also rented an apartment in NJ and lived there during the weekdays.
We decide to file federal joinly, but how should we file state tax for CA, PA, NJ and NY?
Thanks,

You file as a part-year resident for California and Pennsylvania.

You probably are considered a part-year resident of NJ as well.

For NY, you file as a non-resident. You can claim a tax credit on your Pennsylvania return for income taxes paid to NY and NJ.