This is one of many sites on that topic.  I just did a Google search of "Landlord tenant law in Ca".

http://www.rental-housing.com/rental/newlaw.htm

First... the law favors the Tenant very heavily however the Landlord does have certain rights including the righ to terminate tenancy without cause upon 30 days written notice (in the absence of a Lease). The Governor just signed legislation that takes effect Jan 2003 that willr equire 60 days notice and under certain circumstances, relocation expenses.

Right of entry: Unless you have a written rental contract that provides for right of entry, the Landlord may not enter unless you approve. Most rental contracts call for a 24 hour notice (may or may not require written notice). The test is "reasonable access." In any case, the Landlord may not enter "cold" under any circumstance barring emergency (fire, flood, death or threat of significent property loss). If you are given notice and Landlord has reserved the right to enter, then you do not have to be there. If you respond to the notice (in writing), you MAY have the right to re-schedule if, given your circumstance, it is reasonable to ask for an appointment. However the Landlord has the right to expect entry during nromal business hours.

Repair: The Landlord must notify you of a repair at least 24 hours in advance. The Landlord has the right to maintain and protect his investment. Refusal to allow entry will likely result in a 30 day notice to quit.

If you have requested repairs: Always request repairs in writing, noing date and time request was submitted, nature of problem and reasonable parameters for right of entry. Landlord must respond in a reasonable period of time. Three days to a week is reasonable time for routine issues. Issues of habitability (hot water, heat, doors, windows, pest control, sewer problems, or emergencies like gas leak, water leak effecting utility of the premises) require attention within 24 hours. If the repair is not an emergency, make a second request. After the second request, or if an emergency, you may, as a tenant repair and deduct the cost of the repair from your rent. You may do this twice a year to a maximum of two months rent. The repair must be performed by a licensed contractor. Compensation for your time and inconvienence is not covered.

A Landlord acting in bad faith is subject to severe liability. Constructive evition or retaliatory eviction is a BIG mistake for a landlord. Failing to maintain a habitable premiese or serving you with a 30 day notice in retailation to some right you stood up for opens the Landlord to liability. Document wrongdoing, stand up for your right as a tenant.... but if the Landlord is simply standing up for his rights... you are screwed...