If the amount you owe or the amount you overpaid is large, you may want to file a new Form W-4 with your employer to change the amount of income tax withheld from your 2009 pay. For details on how to complete Form W-4, see Pub. 919. If you have pension or annuity income, use Form W-4P. If you receive certain government payments (such as unemployment compensation or social security benefits), you can have tax withheld from those payments by giving the payer Form W-4V.
In general, you do not have to make estimated tax payments if you expect that your 2009 Form 1040 will show a tax refund or a tax balance due of less than $1,000. If your total estimated tax for 2009 is $1,000 or more, see Form 1040-ES. It has a worksheet you can use to see if you have to make estimated tax payments. For more details, see Pub. 505.