Hi I am on L1 visa and I came to US in NOV 2010. I have filed taxes using turbo tax software. Later I came to know that I need to file 1040 NR EZ. What should I do now? I got most of the tax refunded as I worked for only One and half month. What will be refund if I file as 1040 NR EZ. Is it necessary to file that if I have already file 1040 EZ

Yes, you should have filed nonresident tax return. You can also claim moving expenses using Form 3903. Now you need to file amended tax return Form 1040X with Form 3903.

Thanks MukatA for your answer. I want to know that I need to file 1040X only or I need to file 1040 NR also. What deduction will be applicable if I filed 1040 NR? Is standard deduction applicable for me which I got when I filed online 1040 EZ unknowingly?

On resident return, one must report worldwide income for the year. Evidently, you reported only the income earned while in US.
On nonresident return you do not get standard deduction. You get itemized deductions. Read instructions to schedule A (Form 1040). If you job assignment is for less than a year, you can claim transportation, lodging and meals. If you job assignment is for more than a year, claim moving expenses. Your U.S. Tax Return: The U.S. Visas (http://taxipay.blogspot.com/2008/08/us-visas.html)