Both my spouse and I are New York residents.All our employers are in NYC.However,"one of my spouse's employers" had sent both NY's and NJ's W-2 forms for the 2006 year to my spouse,since even though my spouse had never ever physically worked in NJ including the 2006 year,my spouse's "that employer" considered a very small portion of my spouse's income in 2006,roughly between $200---$300,as equivalent training income in NJ,as required by "that employer's employee training policy".So,the questions are: Should my spouse also file the 2006 tax return in NJ,in addition to my spouse's tax filing in NY for the 2006 year? How to calculate my spouse's NY State tax and New York City tax,in 2006,regardless of the NJ tax filing issue? How to calculate my spouse's Federal Income Tax in 2006,accordingly? Thanks.

Technically, you need to file a NJ return as a non-resident to account for the $200 - $300 in NJ income. No taxes will be due to her personal exemption.

Add the money to your total combined federal income.

You also need to add the money to your NY state and NYC income, as both governments taxes ALL sources of income.