I know that Hillcrest medical center has a whole staff of volunteer doulas you can use if you deliver there. Even if you're not planning on delivering there, I bet they would have some good references.
Check out www.beautifulbeginnings.org. They're a wonderful doula referral company with EXCELLENT doulas, serving all of San Diego county. They will listen to your needs and help set you up with a wonderful doula. Highly recommended!
Re: Doulas