It's not entirely clear how ragtime records came to Oz in the first place, but the fact that there is one suggests that SOMEONE there might enjoy it, even if it isn't a member of Ojo's party. So did Oz keep with with the Great Outside World's musical trends after jazz? I don't know. Even though Oz HAS electric power, it never seems to become all that widespread (when Leon describes wiring up his house in Wicked Witch, he treats it as a novelty), which would presumably mean few to no electric instruments, on which most musical styles of the latter half of the twentieth century and beyond have pretty much depended. And I can't really imagine the Emerald City getting, say, a disco or a slam-dancing club. But maybe that's just because I view Oz as remaining somewhat quaint by modern standards, despite the fact that the books actually present us with a fair number of then-modern amenities.
So now that I've talked about the music in Oz itself, I'm wondering what music reminds other people of Oz. I know kevenn has said he usually listens to Tori Amos when drawing Oz characters, and I know there are a few other Oz fans (in addition to me, that is) who like They Might Be Giants. I think songs that bring Oz to my mind are usually ones that mention imaginary themed locations, like TMBG's "Cowtown," and the town of Misery from XTC's "1000 Umbrellas" (which I think might be located in the Munchkin Sadlands, not too far from Tear Drop City). Actually, XTC explicitly refers to the Wizard of Oz in "Merely a Man," and references the Scarecrow and Tin Woodman in "Scarecrow People." There's apparently also an Andy Partridge demo in which he mistakenly credits the Oz books to Frank L. Richards, rather than Baum. (Has anyone ever heard this song? I believe it's called "Rip Van Ruben.") Interestingly, it's an old Oz e-mail list that I partially credit with getting me into Tom Lehrer, who seems quite popular among Oz fans. I don't think there's anything particularly Ozzy about his music (although he does mention the book in "Smut," and jokes that he translated in into Latin in his introduction to Tom Lehrer Revisited), but I guess Oz fans also tend to be bibliophiles in general, and hence probably likely to enjoy music that employs unusual vocabulary and clever wordplay. I believe that both Baum and Thompson were fans of Gilbert & Sullivan, who did much the same kind of songwriting in their own day.
 This is referred to as the Ozian national anthem in Dorothy and the Wizard, which is interesting because "The Star-Spangled Banner" didn't officially become the American national anthem until over twenty years after the publication of this book. There's no indication that the Ozian anthem has the same tune, and I prefer to think it doesn't, but it would be only fair considering that it was a rip-off of "The Anacreontic Song" in the first place. And, of course, "My Country, 'Tis of Thee" reuses the tune of "God Save the Queen."
 There's a reference to a song called "The Land of Oz Forever" in Hidden Valley, which could be either a different song or a pre-Ozma version of the same one.
 For the Books of Wonder edition, "coal-black" was changed to "cross-eyed." I can sympathize with the desire to remove what could be viewed as racist material, but I must say it's an odd substitution.