You can Treat your kids with Zombie Burbz, it a free app that utilizes a variety of Zombies in different situations.
If your kids go trick-or-treating you can have peace of mind of knowing where your kids are by using a GPS Phone Tracker app. It comes free or you can upgrade to a $2.99 versions.
If you want to get really scared this Halloween, download the Haunted Site locator app. This app helps you locate the nearest true haunted spots.