Individuals - If you have an automatic 6 month extension to file your income tax return for 2008, file Form 1040, 1040A or 1040EZ and pay any tax, interest and penalties due.

Partnerships - File a 2010 calendar year return (Form 1065-B). This due date applies only if you were given an additional 6 month extension. Provide each partner with a copy of Schedule K-1 (Form 1065) or a substitute K-1.

Electing Large Partnerships - File a 2010 calendar year return (Form 1065). This due date applies only if you were given an additional 6 month extension. See March 15 for the due date for furnishing the Schedules K-1 to the partners.

Employers - Nonpayroll Withholding. If the monthly deposit rule applies, deposit the tax for payments in September.

Employers - Social Security, Medicare and withheld income tax. If the monthly deposit rule applies, deposit the tax for payments in September.

Employers - Social Security, Medicare, and withheld income tax. File form 941 for the third qurter of 2011. Deposit any undeposited tax. (If your tax liability is less than $2,500, you can pay it in full with a timely filed return.) If you deposited the tax for the quarter in full and on time, you have until November 10 to file the return.

Certain Small Employers - Deposit any undeposited tax if your tax liability is $2,500 or more for 2011 but less than $2,500 for the third quarter.

Employers - Federal Unemployment Tax. Deposit the tax owed through September for more than $500.