If you are one of the many Americans who waited until the last minute to file your tax return, you may be in for some long lines at the post office. April 15th is reportedly the single busiest day of the year for the post office. If you must brave the lines on April 15th, a few local post offices will remain open late. To find out about hours of operation for a post office near you visit the USPS Services locator. Tax returns must be postmarked by April 15, 2010.
Keep in mind that you can file your return electronically through April 15, 2010. If you extend the return, you will have up until October 15, 2010 to file the return. However, even if you extend the return you will still need to make any payments due by April 15. Failure to pay at least 90% of federal taxes due will result in interest and penalties.