Estimated tax payments

I believe the current rules suggest you do not need to continue to make estimated tax payments, if the end result of the sum of prior estimated payments (and withholdings) meets one of the several requirements:
1. The amount of tax payment owed at time of filing is less than $1,000, due to the prior withholdings and/or estimated taxes previously paid.
2. The amounts of prior tax withholding and estimated tax payments is less than 90% of taxes that you will owe for the current tax year, or
3. The amounts of tax withholding and estimated taxes paid are at least 100% of the prior year's tax requirement (or 110% of the tax requirement if adjusted gross income is greater than $150,000 or greater than $75,000 if married filing separately.)

Suggestion: Even if you think you will meet these requirements, you may want to make an estimated payment (for some small amount) which is an indication to the IRS that you are consciously making a lesser payment (vs. forgetting to make an estimated payment).

I am not a tax accountant and although I believe what I have written to be correct, you should read the specific IRS rules, which are available in Publication 505 (Rev 2/2007) – Tax Withholding & Estimated Tax: http://www.irs.gov/pub/irs-pdf/p505.pdf.

A couple of other potentially useful references are:
http://turbotax.intuit.com/tax-tools/determining_estimated_tax_payment s/article
http://www.smartmoney.com/tax/filing/index.cfm?story=estimated