I am student on an F-1 visain NJ.I had filed taxes using 1040NR-EZ till 2008 as a non-resident alien.I got married in 2009, and my husband is on H1-B in California. For 2009 I have filed my NJ state tax a single person (being a graduate fellow I do not pay any state tax). Following that we realised we can file our taxes (Federal) jointly for the maximum benefit.In that case can we file our 2009 Federal Tax jointly and state tax separately as singles? If not, then how do I amend my state tax filing and how to file state tax jointly with me being in NJ and my husband being in CA?For the federal tax if we file jointly, I choose to be a resident for tax purposes, do I need to fill out any forms for doing that, and do I need to pay medicare and social secuirity tax,which I am not paying as a resident alien?

1. If you file joint return as residents for 2009, you must start paying FICA taxes in 2010.
2. Or you can file a nonresident tax return and your husband files as married filing separately (if he is resident for tax purpose).
3. Normally, states require that you file in the same way you filed your federal tax return.
4. If you are filing joint return for CA return, your husband is resident and will report CA income. You are nonresident and does not have any CA income. Your U.S. Tax Return: Working or Living in Two or More states (http://taxipay.blogspot.com/2008/06/working-in-two-or-more-states.html)
5. I am not aware that Graduate fellow do not pay NJ state tax.