It's Wednesday, April 15, and you just woke up to the spring sun shining and the birds singing. All is well with your world until, in a dreadful, stomach-churning moment, you suddenly remember what you'd forgotten to do: file your tax return! 
Video: What to do if you can't pay
Don't panic. Take a deep breath. I have two options for you to consider. Use one of them.
And don't be cavalier about it.
If the Internal Revenue Service can prove willful failure to file, you're subject to a criminal fine of as much as $25,000, and you can go directly to jail -- without collecting $200.
That's in addition to a civil penalty of 5% per month of the net tax due (that's the tax owed after credit for withholdings, estimated taxes paid and other credits on your return), up to a total of 25%.
If your return is more than 60 days late (counting extensions), the minimum civil penalty is the lesser of $100 or 100% of the tax due on the return. And that's just for not filing. There are additional penalties for not paying.
All of a sudden, you feel like your collar is two sizes too small . . . and you're not even wearing a shirt!
OK, now take another deep breath. MSN Money is behind you -- even the IRS is behind you. The IRS would much rather have you file something today than nothing at all. Map: Working for the (tax) man
What to do
If you're stuck, here are your options:
1. Get that return done. If you can get your return done and postmarked by midnight April 15, you've filed on time and escaped the bullet. So sharpen your pencils and get down to work. Use MSN Money's Tax Checklist to make sure you have all the information you need. Then find out which local post office will be open until midnight. Give yourself enough time to get there.
Now, get that return out and work the numbers on both your federal and state returns. Be sure to attach your W-2 and 1099 statements to each when you finish. Check out the latest tax law changes for changes that may affect what you owe. Use MSN Money's Tax Estimator to get a handle on your bill.
Don't forget to sign the returns. If you want to file online with TurboTax, click here.
Don't be concerned if you don't work well under pressure. If you make a mistake and miss a deduction, you have three years from the due date of your return to amend that federal return. (That means April 15, 2012.) To amend it, use Form 1040X. You can download the form from MSN Money (click here) or from the IRS (.pdf file).
To access state income tax forms (if your state has an income tax), click here.
Despite rumors to the contrary, filing an amended federal return doesn't increase your chances of being audited. But you can help your cause. I recommend that my clients attach documentation to their amended returns to back up any additional deductions they claim. In fact, by showing the IRS that you understand the system and do have substantiation, you might actually decrease the odds of a full audit.
2. File for an extension. Video: Expert tips on how to file an extension
Use this option if you really can't get that return done on time. Filing for an extension gives you until Oct. 15 to complete your return (most states will also honor an extension request). You do that by filing Form 4868 for an automatic extension. Download the form from MSN Money or the IRS (.pdf file), or get it in Spanish. It's an easy form to complete.
Be sure to include the following four items:
1. Your Social Security number -- and your spouse's if you're filing jointly.
2. How much you think your tax bill will be.
3. How much you've paid the IRS so far.
4. The amount of the check you're including with your extension form, if you need to include a payment.
More time to file, not to pay
You'll have to estimate your final tax liability and submit any additional tax due with the extension request. This is an extension to file, not to pay. If you overpay, you'll get the balance back as a refund.
You can use Form 4868 to eliminate the failure-to-file penalty. Even if you underestimate the tax due, there won't be a failure-to-file penalty unless the unpaid amount turns to be more than 10% of your total tax bill.
For example, assume your total tax liability is $10,000. As long as you don't owe more than $1,000 (10%) when you eventually file, there won't be any failure-to-file penalty. So, when you estimate the net tax due, estimate carefully.
If you file Form 4868 by midnight April 15, the IRS must give you the full six-month extension. Make sure that you obtain proof from the post office that you mailed your extension request on time. You can do that by sending the extension request by certified mail.
And if you can't make that . . .
Now, what happens on the morning of Oct. 15, when you wake up to the same feeling?
You used to be able to get an automatic four-month extension and then be able to request an additional two months. Not anymore.
First, smack yourself for having so little self-discipline. Then take yet another deep breath. It's only money. The faster you get that return out, the lower the interest and penalties. E-file if you can. But get that return out! Video: How to better prepare for next year
Produced by Peggy Collins / Graphics by Joe Farro
Updated April 15, 2009
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