You can contact the California State Bar at: www.calbar.org.
To search a particular attorney by name or bar number you can go to: http://www.calbar.ca.gov/state/calbar/calbar_generic.jsp?cid=10114
The California State Bar's website allows you to look up certain information about attorneys, such as whether they are currently licensed to practice law and whether they have a public record of discipline. Go to http://www.calbar.ca.gov/state/calbar/calbar_home.jsp, and then click on "Attorney Search" to search for an attorney by name.
In addition, most reputable attorneys these days have websites. Review a prospective lawyer's website carefully, ask lots of questions during an initial consultation, and ask around to find out that attorney's reputation in the community.