You will be taxed as if you were a Citizen (Resident Alien) filing Form 1040 if you are a permanent resident (Green Card Holder) or you were present in the United States for 183 days for the three year period counting all the days in 2011, 1/3 of the days in 2010 and 1/6 the days in 2009.
Tax Tip – Certain individuals may be exempt from the 183 day requirement, for example, if you were here on a Student Visa (F, J, M or Q) or you can show the IRS that you have a closer connection to a foreign country than the U.S.
As distinguished from Resident Aliens who are taxed on their worldwide income, Non-Resident Aliens are taxed only on their U.S. Source Income (by filing Form 1040NR). Many itemized deductions are allowed, though the Standard Deduction of $5,800 is not allowed.
Tax Tip – Non Resident Aliens may be able to deduct their moving expenses to the U.S. provided they work for at least 39 weeks during the 12 month period after the move.
Non-Citizens should reference the specific Tax Treaties with their respective Countries, which will further delineate rules on residency, deductions and the tax treatment of income.