Remember that animated, professionally narrated version of Peter and the Wolf you saw as a kid? Sure you do -- somewhere in the depths of your memory, you'll probably remember this fifteen-minute Disney short from 1946. It's odd to think now that this came out just a decade after Prokofiev's original composition in 1936 -- they both seem sufficiently remote to be ancient history to kids these days. In any case, "Peter and the Wolf" was written to be performed with a narrator (in Russian); Disney added animation and recruited Sterling Holloway to narrate an Americanized version. (You may recognize Holloway's voice from the Winnie the Pooh and Jungle Book films.)
Wikipedia explains some changes in the Disney version versus the original Russian version:
• During the character introduction, the pets are given names: "Sasha" the bird, "Sonia" the duck, and "Ivan" the cat.
• As the cartoon begins, Peter and his friends already know there is a wolf nearby, and are preparing to catch him.
• The hunters get names at a later point in the story: "Misha", "Yasha" and "Vladimir".
• Peter day-dreams of hunting and catching the wolf and exits the garden carrying a wooden "pop-gun" rifle with the purpose of hunting the wolf down.
• At the end, in a complete reversal of the original (and to make the story more child-friendly), it turns out that the duck has not been eaten by the wolf. (The wolf is shown chasing the duck, who hides in a tree's trunk. The wolf attacks out of view, and returns in view with some of the duck's feathers in his mouth and licking his jaws. Peter, the cat, and the bird assume the duck has been eaten. After the wolf has been caught, the bird is shown mourning the duck. The duck comes out of the tree trunk at that point and they are happily reunited).
In the original Russian version, the story ends with the line: "If you listen very carefully, you'd hear the duck quacking inside the wolf's belly, because the wolf in his hurry had swallowed her alive." Anyway, enjoy: