I have been on student f1 visa all for the year 2008 and have been in usa for more 300 days of the year. I checked a few websites but am confused about my tax filing status for the federal taxes. For becoming a resident for the tax purposes I fail the green card test however I pass the substantial presence test since I was in usa for more than 183 days of the year 2008. What tax form should I fill, 1040 ez or 1040 nr ez?

On F1 you are exempt from residency for 5-years. You must file non-resident tax return Form 1040NR or 1040NR-EZ and Form 8843. Your income is not subject to FICA taxes but you must pay federal and state income taxes.

On your F1 income you will get deduction based on tax treaty between the U.S. and your country. Read: Your U.S. Tax Return: U.S. Tax Filing Requirements for Non-Residents