Scoutorama.com offers two good skits for children as of 2015: "The Ugly Halloween Pumpkin" and "Halloween Run On." Pack 114's website includes a large selection of Halloween audience participation skits for kids. The blog Let's Skit Busy! has an archive of church-oriented Halloween skits with themes focused on Christian ethics.
Girl Scout and Cub Scout websites often have archives of skits for kids. These tend to include specific references to the scout organizations within the skits, which can be easily customized for any group. Original skits can also be drawn from classic horror stories such as "Frankenstein" or "Dracula" with just a little tweaking to make them kid-friendly.