You would need to file Form 1065 "US Return of Partnership Income" for the period ending 2008. This return is filed with the IRS, Internal Revenue Service that is, to the US Federal Government. The due date for this form is April 15, 2009. For your information, this return would not result in any federal income taxes as such.
You can click on the following link to access the instructions to the IRS Form 1065 Instructions.
http://www.irs.gov/pub/irs-pdf/i1065.pdf
In addition, you are also required to file Form 165 "Arizona Partnership Income Tax Return" with Arizona State. This is also due on April 15th, 2009.
You can click on the following link to access the instructions to the Arizona 165 Form.
http://www.azdor.gov/Forms/2008/part...65%20instr.pdf