Hi,
I am a German citizen who came to the US in Dec 2006 on a green card that I won in the diversity lottery. I have been working here as a postdoctoral researcher since January 2007. My only source of income is a fellowship from a german research foundation.
Can I still claim the tax treaty benefit for the scholarship as a foreign national, even though I am also taxed here as a resident?
Being confronted with the US tax system for the first time I am a little confused. If the tax treaty does not apply to my case, do I also have to expect a penalty for not having paid estimated taxes on my income during 2007?
Thank you very much for all your answers in advance!

Since you have a green card, you can't claim treaty benefit. You must file resident tax return for 2007. You will get standard deduction and exemption deduction and all deductions available to citizens or residents.