I just watched Django (1965) starring Franco Nero.
I had no idea there was an original film with this name...made when Sergio Leone was just starting the realistic, violent genre of Spaghetti Westerns. Director was Sergio Corbucci, a contemporary of S Leone, and it was a trip. There was even a machine gun in it, not real realistic, but really violent! And Italian.
The Tarantino film completely ripped off the entire song from the original flim, it is seeminly the same singer and exactly the same cheesy song.