"Media should work for you and within your family values and parenting style. When used thoughtfully and appropriately, media can enhance daily life. But when used inappropriately or without thought, media can displace many important activities such as face-to-face interaction, family-time, outdoor-play, exercise, unplugged downtime and sleep."
Make your plan at HealthyChildren.org/MediaUsePlan.
Personal Note: Healthychidren.org has a wonderful series of advice for parents. I have saved each of them and have made them available at this link.