I have a follow-up question:

My husband lives and works in PA, so his state income is apportioned entirely to PA. I live in NJ, and work in Pa. My income is apportioned entirely to NJ, with no income to PA (at least none was apportioned to PA. We want to file joint state returns to be consistent with our Federal filing, however, when I did the taxes, it appeared that we owe taxes in NJ and PA. I believe one of us would be considered a non-resident, so I am thinking taxes should not be owed to both states, only one. Can we file a joint return for federal taxes and separate returns for state taxes? If not, who would be the non-resident? How can we achieve the greatest benefit from our joint filing given the aforementioned example?

Normally, the states require you file the same way you file on the federal return.

You should BOTH pay taxes to PA, but NJ will give you a credit for the taxes YOU pay to PA, and that SHOULD offset the NJ tax enough that you owe nothing, becauas eoyu are only paying taxes to NJ on YOUR SALARY, not your husband's salary.

It would be best if you got professional help to file your tax returns.