I’m an international graduate student from Sri Lanka and I came to the US in 2003. Last five year I file my tax return using 1040NR. I heard that if you are in the US on F1 (student) visa for more than five years, you are consider as a residence alien for the tax purposes. My quotation is since this my sixth yeas in the US, can I file my tax return this time using form 1040 instead of 1040NR. Also I have two children who were born in US, and my spouse is in F2 visa and unemployed. We are filing jointly. Am I eligible to clam Earn income tax credit (my annual in come is under $20,000). Please can some one answer my quotation?
Thank you.

I am in a slightly similar situation and I would recommend you to read publication 519 from the IRS (http://www.irs.gov/pub/irs-pdf/p519.pdf) \. Regarding the 5 year rule, pages 6 states: "you will not be an exempt individual as a student if you have exempt as .... a student for any part of more than 5 calendar years unless you establish that you do not intend to reside permanently in the US"... whatever that means

Good luck

You got F-1 in 2003 so you were nonresident for 2003, 2004, 2005, 2006 and 2007.
In 2008 you should have filed resident return. For 2009 file resident return.
You can file amended return for 2008.