Go to the local West Marine, BoatUS to get Latitude 38, or get it on line. http://www.latitude38.com/LectronicL...tronicLat.html
It's free, and it's the sailing mag for the West Coast.
San Diego is a good place to find people looking for a crew member. Any yacht club that runs races will be a good place to get onto a boat. The bonus is you learn about racing, a very good way to learn to read the wind and a lot about sail handling, and the limits of a boat's capabilities. Work at it for a year and you will have most of the boats heading for Baja in there next October/November for the Baja Ha Ha where you should be able to pick up a spot.