The last (of 4) payment for 2008 estimated taxes is due on Thu, Jan 15, 2009, that is if you don’t plan on filing your taxes by Feb 2, 2009.
In most cases, for 2008, you must make estimated tax payments if you expect to owe at least $1,000 in tax for 2008 (after subtracting your withholding and credits) and you expect your withholding and credits to be less than the smaller of:
- 90% of the tax shown on your 2008 tax return, or
- 100% of the tax shown on your 2007 tax return (110% if your 2007 adjusted gross income is more than $150,000)
Updated (1/19): Here are the links for 2008: