Life

Go Ask Alice! - "Columbia University's Health Question and Answer Internet Service."
Kidshealth (for Teens) - reliable, up-to-date medical information.
I Wanna Know - The American Social Health Association provides "answers to your questions about teen sexual health and sexually transmitted diseases."
Lovegoodbadugly.com - "A guide on love, respect, and abuse in relationships."
California Department of Motor Vehicles (DMV) - sample California DMV written tests.
Consumer Education for Teens - this site was done in Washington, so some of the legal information may be a bit different, but there is useful consumer information here that still works for California.
Teen Space @ Internet Public Library