A VERY interesting update on the copyright case with Jib Jab I blogged on earlier, from EFF Deep Links via the Volokh Conspiracy:

"Turns out Woody Guthrie lifted the melody of "This Land is Your Land" essentially note-for-note from "When the World's on Fire," a song recorded by country/bluegrass legends, The Carter Family, ten years before Guthrie wrote his classic song. Here's a short snippet (380k mp3) of the song (the song can be found on the box set, The Carter Family: 1927-34). You don't need to be a musicologist to hear what we're talking about."

The article points out the letter from the "litigation counsel for Ludlow Music Inc." emphasizes how Jib Jab lifted "the entire melody, harmony, rhythm and structure of the [sic] Mr. Guthrie's song."