There is a fold out card that is designed specifically to teach children how to pray the rosary. If the kids are not able to read yet, they will need adult help. It's called "The Rosary for Children" and includes the Luminous Mysteries. I gave it to my CCD kids this year; IIRC the local religious shop charged 50 cents per card. You can view it here.
The front side of the card has the different mysteries along with an illustration and a comment for each of them. The back of the card has a brief explanation on how to pray the rosary, the basic prayers:
- Apostles' Creed
- Our Father
- Haily Mary
- Glory Be
- Hail, Holy Queen
and a diagram [approximately 3 1/4 inches H x 2 1/8 inches W].
For young eyes, the diagram is okay. For older eyes like my own, I suggest getting out the glasses
Hope this helps!