This resource is a best kept secret. After your baby is born, contact the Parent Connection Playgroup coordinator (it used to be called Las Madres, and is organized by Scripps Hospital) and ask if there is a playgroup yet for your age group in your area of the City.
I made some of my best friends in San Diego through my children’s play groups. Of course, it doesn’t always work that way. Like anything else, you need to attend, meet some people and see if you and your child click with the people. However, Parent Connection often times has several playgroups in an area based on the same age group, they also offer language oriented groups and even interest/topic groups.
More information on the Parent Connection playgroups here: http://www.scrippshealth.org/Services.asp?ID=228&pID=226
There is a minimal $20/year fee to become a member of Parent Connection and join a playgroup and they send a handbook each month with discounts and other information as well. I always felt the $20 was money worth spent as I gained so much in my life and my children’s lives from this group.