John Prine, the "Singing Mailman," delivers again

John Prine started writing songs while delivering mail in Chicago in the late 1960s. Over the last 50 years, classic tunes just seemed to pour out of him – some sad, like "Angel From Montgomery" and "Sam Stone"; some funny, like "Illegal Smile" and "In Spite of Ourselves." Now, after beating cancer twice, the 72-year-old Prine is back with a new album, "The Tree of Forgiveness," and it's turning into the biggest record of his career, debuting at #2 on the Billboard Rock and Country charts. Anthony Mason pays a visit to Prine (whom Rolling Stone calls the "Mark Twain of American Songwriting") at his home in Nashville.