When starting a business in California, start your research at these two sites:
The California Business Portal & The Secretary of State's Starting a Business page.
On the SOS' page, you'll see the Secretary of State details 5 recommended steps:
1) Write a business plan
Here are a couple of posts I've devoted to this subject - Business Plans: A Quick Guide and Piecing Together the Business Plan.
The Small Business Administration has a handy page about writing a business plan.
2) Deciding on a location for your business
If you need assistance, check out the Labor & Workforce Development Agency's Business Investment Services page.
3) Choose a business structure
Entrepreneur has a great article on this subject, Choose Your Business Structure.
Click here for those documents.
5) License & Permits
Check both of these sites: CalGOLD and the CA Department of Consumer Affairs.
The Secretary of State also has a listing of business resources - check here.