Hi All,
I think I might have done something wrong with the taxes. I am a foreign national born in 1978, and I was in the US for the following years:
1989 - F2 visa, got SSN, 180 days, did not file tax,
1990 - F2, full year, did not file tax,
1991 - F2, 180 days, did not file tax,
2006 - F1, 170 days, no income till May '07,
2007 - F1, full year, filed 1040NR-EZ,
2008 - F1, full year, filed 1040EZ,
2009 - F1, full year, filed 1040EZ,
2010 - F1, will be a full year.

Should I have filed 1040NR-EZ for 2008, 2009 and the coming 2010? Or I have gotten the resident status for tax purposes already? If I should have filed 1040NR, should I amend the errors with a 1040X ?

Thanks so much for your time!
Ray

Yes, for 2008, 2009 and 2010 you should file nonresident tax return.

Agreed; your status as being EXEMPT from the Substantial Presence Test expires on 31 December 2010.

For 2011, you will file as a resident, UNLESS you prove to the IRS that you have maintained a closer connection to your home country.

Thank you both for your help! I guess I should start filing the 1040X now :(

If you are filing resident form and paying social security and Medicare tax, you should file resident form for 2010. It is highly unlikely that IRS will ask you to file nonresident form.