A rather cute but short webcomic was done not long ago by "Lily-pily" of a crossover between Oz and The Nightmare Before Christmas titled Oz Of Halloween.
The story takes place a year before the original Nightmare movie where Scraps the Patchwork Girl wanders into Halloween Town, while Sally is mistaken for being her by Scarecrow and Jack Pumpkinhead. They are then both abducted by Princess Mombi(the version of Mombi from the Return To Oz Disney movie), who are ultimately rescued by Jack and Scarecrow, plus Ozma. Jack Skellington then arrives and is inspired by Jack Pumpkinhead to dress up like him for the next Halloween.
It's a nice comic, and worth checking out before you go trick-r-treating!