If you are a corporation (because you have a smart CPA on your side), your corporate quarterly estimated taxes are due tomorrow, 12/15/09! You can either deposit your estimated taxes with IRS Form 8109 at your bank, or mail Form 8109 with your check, made payable to “Financial Agent,” to Federal Tax Deposit Processing, PO Box 970030, St. Louis, MO 63197. Don’tcha just love sending your money to the government?! After all, they manage it so well! Sure.