Science Kids has a great collection of videos and lesson plans to help you teach the basics of chemistry.
The American Chemistry Society has terrific resources and lesson plans for K-8 educators. Inquiry In Action, for grades K-5, features standards-aligned lesson plans with multimedia resources. Interested students will enjoy exploring the Adventures In Chemistry Kids' Site. A collection of hands-on experiments for the classroom focus on chemical changes, states of matter, and material properties. For primary grades, Science ABCs introduces chemistry concepts with rhymes, animations, and activities. Middle School Chemistry is designed for grades 6-8.
For K-2 teachers, the Ruff Ruffman Show from PBS is a great resource for teaching beginning Chemistry concepts. The collections includes complete teaching guides, five engaging videos, Cookie Creator game, and hands-on activities.