You can post on Girlz Gone Riding Los Angeles and Girlz Gone Riding Inland Empire and Girlz Gone Riding San Diego depending on where in SoCal you are at

Craigslist also works great. A lot of people do use the Bicycle Blue book for pricing reference as a buyer. So, if you price high, you might not get a lot of people emailing you. Put out a lot of "tags" at the bottom of your Craigslist ad so that you can get more people looking at your ad