We showed this inspired film at Ebertfest 2009. It ran into copyright trouble involving the old records it used. Nina Paley then sidestepped copyright laws by making the film a gift under Wikipedia's Creative Commons. It has found so many admirers that it's now #42 on IMDb's list of the 50 Best Musicals of All Time, right there between "The Many Adventures of Winnie the Pooh" (1977) and "The Jungle Book" (1967).
My blog entry, Having Wonderful Time, Wish You Could Hear.
My review of the film, sharing some wordage from the earlier blog.