Myra started writing a series of books for children based on the "...Are You For Real?" theme back in the seventies. I own several of them and my family really enjoys them. They give children the straight scoop on many "myths" of the holidays we celebrate and talks about how Christians should respond to these holidays.
In "Halloween Are You For Real?" a family talks about the holiday and the parents explain the early pagan origins of Halloween. It goes on to explain how the Church responded to this holiday by creating All Hallows Eve as a way for people to remember their family members and other Christians who have died in a godly way. The book suggests that Halloween can be spent celebrating the hope that those people had in Jesus Christ for their salvation from their sin. There is a discussion about fear and how as Christians we don't need to be afraid because of that relationship.
I highly recommend this book as a tool to teach your children about Halloween and how to see it in a godly light, not participating in evil practices but celebrating our faith. I think this book would be a good starting place for a discussion of salvation and also helpful for children who are scared of the dark. I found it very praiseworthy.