Which country introduced income tax first?

What do I need to know about filling tax return in the USA? It's my first time and I'm abroad (but with some income from the US).

• I do have an ITIN code so I am legally a US tax payer without living in the States. I have some income from within US and some in another country, which has dual-taxation avoidance treaty with the US. I need a bit of advice / perspective about how and when to fill my tax return with Uncle Sam.

• Answer:

  Assuming you were not actually present in the US during a significant portion of 2011, you will need to file a Form 1040NR.  You can find the form on the IRS website at http://www.irs.gov/pub/irs-pdf/f1040nr.pdf and instructions at http://www.irs.gov/pub/irs-pdf/i1040nr.pdf. The form is due to the IRS by April 17, 2012. If you were in the US during the past 3 years, read the section in the instructions on "substantial presence" to see if you should be filing a form 1040 instead. You should have received a Form 1042S for your US connected income and will use that information to complete the 1040NR form. You might also consider hiring a US tax professional to assist you if the instructions and forms are confusing to you.