If you are an international student seeking to study in California, here are two websites with information to help get you started in achieving this goal:
http://www.internationalstudent.com/study_usa/
http://www.studyusa.com/
 
If you are a U.S. resident seeking to study in California, here are two resources you might check out:
 
1.) SchoolFinder, which includes the contact information for California schools (pre-college): http://www.education.com/schoolfinder/
 
2.) CaliforniaColleges.edu, which includes a variety of information for attending college (or taking courses at colleges) in California: http://www.californiacolleges.edu/
 
I hope these resources are helpful to you. If not, please provide more information about your interest in studying in California, such as the type of school you'd like to attend, or specific types of courses you'd like to take. Thanks!