Co-op Living
Imagine living in a mansion with all your best friends and having big communal dinners every night!  Living in a co-op, you'll share a house with anywhere from a few to over a hundred people.  Food, housework, and decision making is generally shared.  Also known as shared housing or collective housing.

Want the privacy of your own unit but community as well?  Cohousing is a model where residents live in individual apartments or houses, but share some meals, activities, and management duties. Both rental and ownership options available.  Cohousing can range from rural ecovillages to urban apartment complexes to retrofit cohousing made up of several adjacent houses in an existing block.

Limited Equity Housing Cooperatives (LEHC)
LEHCs are a legal structure for a community that offers affordable ownership.  Purchase and sale prices of homes in an LEHC are limited.

What's it like?
The It's a Co-op blog contains details and floorplans of typical co-ops and cohousing communities.
Where can I find it?

Throughout the Bay Area
East Bay Cohousing (EBCOHO) - Not just for the East Bay! - offers a directory of cohousing and co-op communities throughout the Bay Area, tours, information on vacancies, and groups of people seeking to form communities that are looking for additional members. 
SF Bay Area Looking for Housing is a mailing list for room vacancies in co-op houses.
Fellowship for Intentional Community has a directory of co-op and cohousing communities throughout North America.   See their Classifieds section for forming and joining communities.
Bay Area Conscious Community Housing Board is an invite-only group for housing in co-op houses.

Radical Housing is an open Facebook group for radical spaces.

Trans* Housing: SF Bay Area is a Facebook group for trans* people.

QTPOC Housing Bay Area is a Facebook group for queer and trans* people of color.

CoopNetwork has a list of existing co-op and cohousing communities, both LEHC and market rate.

Bay Area Rooms and Apartments is general purpose a Facebook group for finding roommates.
East Bay
The Berkeley Student Cooperative offers low cost, cooperative living houses and cohousing style apartments to university students throughout the greater Bay Area. Housing is available during the academic year and summer and applicants can choose from 20 different houses and apartments, including a range of themed living houses: LGBTQIA & queer, people of color, African American, woman identified, vegetarian, and substance-free academic themes.

East Bay Degobah System is an email list.

San Francisco
SF Chalkboard is a mailing list of co-ops in Sn Francisco.

SFWiki has some general information on finding housing in the Bay Area

General tips
The Beast Housing blog offers tips and advice for finding a spot in a cooperative community.

San Francisco Tenants Union has a list of tenant rights in SF.

Oakland Wiki has a list of Tenant Rights in Oakland.

How can I make my existing place cooperatively run?

The Bay Area Community Land Trust (BACLT) provides training and assistance to tenants that want to convert their community to a resident owned and managed limited equity housing cooperative (LEHC).

The San Francisco Community Land Trust (SFCLT) assists tenants in San Francisco in converting their buildings into LEHC's.

The Northern California Land Trust can also assist residents seeking to convert their property to a co-op