Tax day has come and gone for most people, but your dealings with taxes may not be done.

Internal Revenue Service spokesman Dan Boone offers these tips for handling some typical after-tax-day issues:

Didn’t file by April 15? It’s too late to request an extension of time to file, so the important thing is to file your return as soon as possible.

If you owe taxes with your return, you may be charged interest and penalties on anything not paid by April 15, along with a late-filing penalty. To reduce the penalties and interest, pay as much as you can with the return.

If you’re due a refund and are filing late, you probably won’t be penalized, but you could lose the refund if you don’t claim it within three years.

Want to check the status of your refund? Visit IRS.gov and click on “Where’s My Refund?”. You’ll need to input the primary Social Security Number on your 2009 return, your filing status (Single, Married Filing Jointly, etc.) and the exact amount of refund you expect. If you don’t have Internet access, call 1-800-829-1954 for 24/7 automated refund information.

Not happy with the amount of your tax refund? Fix it now for next year by adjusting the amount you pay in. If you’re an employee, use the IRS’s online Withholding Calculator to figure the correct status and number of allowances. Then adjust your withholding by filling out a new Form W-4 with your personnel office. If you’re self-employed, adjust your estimated tax payments. And if you’re not making estimated tax payments, you can start June 15, the next due date, by using Form 1040-ES. Visit IRS.gov for details.

Need a payment plan? If you owe the IRS $25,000 or less and can’t pay it all, visit IRS.gov to apply for an online payment agreement. The $105 set-up fee drops to $52 if you pay by automatic debit. Lower-income applicants may qualify for a reduced fee of $43. If you don’t have Web access, call 1-800-829-1040 to set up an IRS payment plan.

Want to e-file your tax return now? E-file and Free File are still available through Oct. 15, the filing deadline for those who requested an extension by April 15. But even if you didn’t file an extension, you can still e-file your return.

Use the tax software you bought, or if your 2009 adjusted gross income was not over $57,000, use the IRS Free File program. CAUTION: To avoid tax scams or unnecessary fees, access Free File only through IRS.gov.

Realized you need to fix an error on your return? The IRS will usually correct math errors and may even accept returns with certain forms or schedules left off. But if, for example, you forgot to include reportable income or a deduction or credit, you can file a Form 1040X to amend your return.

The form is available at IRS.gov or by calling 1-800-TAX-FORM. Be sure to wait until your original return has processed before trying to amend it. Generally, you have three years to amend a tax return.

Got an e-mail from the IRS? Beware! The IRS will never contact you about your taxes via e-mail. If you get an e-mail that appears to be from the IRS about your refund or directing you to a Web site, it’s probably an attempt by scammers to steal your private information. Don’t click on any links in the message – forward the fake e-mail to phishing@irs.gov mailto:phishing@irs.gov using the instructions at www.irs.gov file://www.irs.gov .

Need help with a tax problem? If you encounter a federal tax problem, contact the IRS immediately. Waiting can cost you time and money. If you get a notice from the IRS, call the phone number on the notice for help.

Or call the general IRS help line toll-free at 1-800-829-1040. If you’ve tried the normal IRS channels and the problem still isn’t resolved, contact the Taxpayer Advocate Service toll-free at 1-877-777-4778 for free assistance.