Maybe the Jataka tales
are what you want. They are quite suitable for children and have a moral.
How old are the kids?
I don't know that a kid under, say, 10 would really understand rebirth. There are a lot of adults that don't understand rebirth. But all children should learn about death (keep 'em in line, buwahahaha). Just keep it gentle by pointing out death when it is visible. Explain that all things end: like day turns to night, so life changes to death. Encourage kids to observe the first precept. When they take to stomping bugs, ask them questions in an attempt to get them to empathize with the bugs, and with those that have died. My own young kids understood, and then became protective of small animals. They begin to understand that things die, and that all beings want to avoid death. Important lessons.
As for rebirth, I would depersonalize the idea if they're really young. Don't teach them that 'they' will be reborn. Teach about how other beings are reborn, and how principals of virtue affect such things. When they get old enough to form conclusions of their own, then talk about it.
EDIT: I keep adding to this. Sorry.