Originally, Patrick Stewart was going to narrate for the film adaptation, but it was scrapped for some reason. A few little tidbits were lost from Patrick Stewart's monologues, although no Mr. Oogie Boogie is to be found in the original poem. If you're a true Nightmare Before Christmas fan, it is well worth a listen. I would also highly recommend reading the original book with Tim Burton's original art work.
Lastly, the original soundtrack has this little gem. Once again, Patrick Stewart provides narration.
Yes, Jack and Sally had Skeleton children, and of course they formed a xylophone band!