If you waited until the last minute to file your taxes, that minute is here. Taxes are due in the mail by midnight. The United States Postal Service will continue to postmark tax forms until 11:59 p.m. tonight. You're encouraged to drop off your returns early in the day, check collection times and make sure you have proper postage. Postage rates for First Class Mail are 44 cents for the first ounce and 20 cents for each additional ounce. People who want to certify that their tax forms are received by the IRS should mail them using Certified Mail Service. The deadline was extended from April 15 to April 18 this year because of a holiday observed in Washington, D.C.