Hi,
I have a quick question. My situation is the following:
My mother arrived to US with a green card in June and my father joined us later in September. My husband and I provide both of them with food, shelter and living expenses. My mother made less than $600 as a consultant for a school in 2008 and therefore was not issued a 1099. So my questions is: I know I will be only able to claim my mother as a dependent because she lived with us for over 180 days, but does she have to file a separate income tax with my father (he had $0 income in 2008)? They also have another daughter age 18 here on F1.
I would appreciate an answer! Thanks!

Your mother and father are under the filing minimums so they need not file at all.

You may take her as a dependent.

You can claim your parents if you provided more than half of their support for 2008 and they did not earn more than $3,500. It is not required that they live with you. For the requirements to claim a dependent (as your qualifying relative), read: Your U.S. Tax Return: Requirements for claiming a dependent

Your mother must file tax return as her self employed income is $400 or more. You will report your income and expenses on schedule C or C-EZ (Form 1040). Then you put net income (or loss) on line 12 of Form 1040. This income is subject to SE tax at 15.3% (this is shown on line 57 of Form 1040). Half of SE tax is deductible on line 27 of Form 1040. Read: Your U.S. Tax Return: Tax Filing by Self Employed Sole Proprietor or Independent Contractor

I have to side with Five Rings on this one.

If the mother's net income was $400 or less, then NO self-employment taxes are due. Even if she made between $400 and $600, normal business expenses (use of cell phone, transportation costs, office expenses) would reduce her net Schedule C income to less than $400, meaning no taxes would be due.

This being the case, her filing a tax return would be a waste of time.