April 18 is the deadline for filing your 2010 federal income tax return to the Internal Revenue Service this year. But do you need to file for an extension beyond the IRS's gift of an extra three days? Maybe you need more time because of late 1099 reports from your financial institutions or perhaps you're just a habitual procrastinator?

Thankfully, it's now pretty easy to get an extension for filing an income tax return.

The IRS' Free File system online allows you to prepare and file electronic Form 1040s as well as Form 4868, the form needed to file an extension.

Those not using Free File can use commercial tax preparation software, such as TurboTax and H&R Block At Home (formerly TaxCut), to electronically fill out and file IRS Form 4868.

But be careful. Filing an extension doesn't mean you can procrastinate forever--or Scot free.

If you think you owe income taxes for 2010, you'll need to send a payment of your estimated tax payment to the IRS along with your Form 4868 by April 18, 2011. Otherwise, the IRS will add penalties and interest for the original tax payment, which could increase what you owe by 25 percent or more. (Massachusetts and Maine residents, who observe Patriots Day on April 18, have until Tuesday, April 19 to file their state returns but must file their federal returns by the 18th along with everyone else.)

Naturally, if you're expecting a refund from the IRS for the income taxes you already paid in 2010, there's no penalty in asking for extension—except for the fact that the government will have your money. And if you fail to file your tax return within three years of the due date, the government gets to keep any refund!

For other 2011 federal income tax report preparation tips, see the Consumer Reports Money section.

IRS 2010 Form 4868: Application for Automatic Extension of Time To File U.S. Individual Income Tax Return (PDF) [IRS]