FILING A TAX RETURN

is about as fun as a migraine headache, but now there's a pain reliever: Many U.S. taxpayers can file online, free of charge.

Why the gift? Online filing (which automatically does the math that many filers get wrong) significantly cuts down on errors, saving the IRS time and money. And for taxpayers, it has the added advantage of offering refunds within 10 days for those who use direct deposit. (With paper returns, that typically takes six to eight weeks.)

To qualify, the one overarching requirement is that you must have adjusted gross income of $54,000 or less. Beyond that, the 19 online-tax-software companies that have partnered with the IRS to offer this service may have added additional restrictions, such as age limits or state residency requirements.

So what's the catch? First, to use these services for free, taxpayers must access them through the IRS Free Filing web site. If you go directly to the company's site, you'll end up paying the regular filing fee (usually about $20 or so). To make sure you're not going to be hit with that fee, go through the IRS web site every time you log on to your account.

Also, if your taxes are fairly complicated, you might want to shell out the extra cash for a paid service that includes some extra bells and whistles. For example, with TurboTax Deluxe (which is available through its web site for $29.95) you'll get help calculating your deductions with the company's deduction maximizer something that is not available through its free file program.

Finally, be sure to read all the fine print carefully. Chances are you'll be pitched additional fee-based services (like audit protection or refund-anticipation loans) that you may not need. And if you want to file your state return along with your federal one, prepare to pay up because most of these preparers charge for state returns.