I am drawing widow benefits & 66 years old - I work partime and will be given a 1099. How much can I make without filing federal taxes?

I believe the general filing requirement for 2009, single, and over 65 is $10,750. HOWEVER, if you self-employment income is $400 or more you are required to file a return. You may not owe any income taxes in that case, but you may owe self-employment taxes.

What is the nature of the Form 1099? Is it for contract work, or is it for interest (Form 1099-INT) or dividends (1099-DIV)?