J.E.
We loved Alice's Montessori preschool and kindergarten. Children can start as young as two (no need to be potty trained) and can continue through kindergarten. The teachers are great! http://www.alicesmontessori.com/
For elementary school, both my children attend Eagle Peak Montessori school. It is a charter school in the Mount Diablo School District. We love it! http://eaglepeakmontessori.org/