Many voting questions can be answered here: http://www.sos.ca.gov/elections/elections_vr.htm
The following are some highlights from the above webpage:
Frequently Asked Questions
This webpage contains information about registering to vote in California. If you have a question that you do not see answered here, please visit our Frequently Asked Questions page.
Are You Already Registered to Vote?
To find out if you are currently registered to vote, contact your county elections office. If you are not registered to vote, you can ask your county elections office how to register or you can follow the simple steps [on the page we linked to above].
How You Can Register to Vote
Fill Out A Voter Registration Form Now
Click here (ENGLISH/ESPAÑOL) to download and complete the voter registration form on your computer. When you fill in your address, the address for your county elections office will automatically be added. Then simply print the form, sign it, and mail it directly to your county elections office.
Pick Up A Voter Registration Form
You can pick up a voter registration form at your county elections office, library, or U.S. Post Office. It is important that your voter registration form be filled out completely and be postmarked or hand-delivered to your county elections office at least 15 days before the election.
When to Re-Register to Vote
You will need to re-register to vote when:
You move to a new permanent residence
You change your name
You change your political party choice.
For additional assistance with voter registration, please contact the Secretary of State's office at the following toll-free number: (800) 345-VOTE.