BASCon: Annual slash con, held in the San Francisco area. Most recent is November 7-9, 2003.
BayCon: General science fiction and fantasy convention, held in San Jose over Memorial Day Weekend.
Blars' Con Listing: Listing of conventions in southern California with links. [Aggressively blocks access to domains he considered "spammers".]
California Science Fiction, Fantasy, Horror and Gaming Convention List: A listing of conventions held in California, detailing location, price and accommodations for each.
ConDor XI: A media and literature convention that focuses on general science fiction and fantasy.
ConJecture 3: Annual science fiction and fantasy convention with an emphasis on literary programming and events. Held in San Diego.
Conucopia: 1999 North American Science Fiction Convention: Held August 26-29 in Anaheim. Includes program and image gallery.
Darkstar Science Fiction and Gaming Club at UC San Diego: Information on meeting and gaming times, library hours, and activity schedule.
Fantastic Frontiers: Holds monthly meetings around Sacramento, also running "Star Struck", July 9, 2005. Site includes event list, Halloween party pictures, and contact information.
Los Angeles Science Fantasy Society (LASFS): General information on the North Hollywood group that runs Loscon, an annual convention, which takes place in southern California. Weekly social and business meetings.
LosCon: Held annually on Thangsgiving weekend in the Los Angeles area. Includes information on memberships, guests of honor, and hotel for the next convention, links for past conventions, and a history of LosCon.
Orange County Science Fiction Club: Monthly meetings in Fullerton.
San Diego in 2006 - Westercon 59: A bid for a convention to be held July 1-4. Includes registration form.
San Diego Science Fiction Conventions, Inc.: Runs science fiction conventions in the San Diego area.
SiliCon 2004: Silicon Valley's annual convention. Located in Sunnyvale, September 3-6, 2004.
Silicon Valley in 2007 - Westercon 60: A bid for a convention to be held July 5-8, 2007. Run by SPFII (Society for the Promotion of Fannish Interests, Inc.).
Stone Hill SF Association: The oldest SF club in the Tampa Bay area. Meetings once a month.
The San Francisco Bay Area Science Fiction Association (BASFA): Social group with weekly meetings. Includes location, schedule, and information on the pun tax rule.
USS Defiance, NCC 1717-E: Star Trek fan club in Sacramento California. Site contains general information about meetings, and events, and has a list serv.