Here's a simple guided meditation that can be read to children as they sit quietly.
Our monks encourage the children to sit with their legs crossed, hands on their laps, with open right hand over open left hand. A gong, bell, or chime can be used to begin the quiet.
The children take a deep breathe in and then out. They're encouraged to concentrate on their tummies moving out and in as they breathe in and out.
Then the leader can peacefully recite the following for the children to hear as they breathe:
May I be free from suffering.
May I be free from anger.
May I be cured from illness.
May I be free from fear.
May I be free from hatred.
May I reach peace and tranquility.
For older children this can be extended universally:
May my parents be free from suffering.
May they be free from anger.
May they be cured from illness.
May they be free from fear.
May they be free from hatred.
May they reach peace and tranquility.
May (my teachers, relatives, friends, enemies, all living beings) be free from suffering...
Keep the silent meditation time short. Maybe one or two minutes at most. That's a long time for little wiggle worms. A gong, chime, or bell can be rung again to end the meditation. We usually begin our Dharma Sunday School this way.
Keep it simple.
Lighting a plain candle, burning some incense or offering flowers before an image of the Buddha is nice. But don't go overboard. The less pomp and circumstance surrounding meditation with young people, the easier it will be for them to turn to meditation for peace throughout their day, where ever they are. This can become a wonderful tool for parents to help their children during challenging times.
Use what you have.
I've found some very nice, simple chants and meditations for children on the net. Here are a few of them:
Buddhanet has The Loving Kindness Chant broken up in simple lines in both English and Pali here.
Gregory Kramer has a beautiful version of this chant for children here.
May I Be Well, Happy and Peaceful chant can be found here. (WorldPrayers.org)
If you're looking for a simple book to introduce meditation to children, I would recommend Each Breath A Smile, by Sister Susan, based on Thich Nhat Hahn's teachings. It's beautifully illustrated. The text is simple enough for 3 year olds but rich enough for older children.
Savor this experience. There is something very special about meditating with kids. Perhaps, if we as adults approached meditation with the same simplicity as our children, we would move more quickly to emancipation.
May all be free from suffering by the power of the Triple Gem!