Historic Sites of Los Angeles Digital archive of Historic Los Angeles by the USC archives, part of their very interesting "Los Angeles Past, Present and Future program.
Los Angeles Public Library's "Electronic Neighborhood" The "LAPL Indexes" are an outstanding archive of old frequently asked questions (FAQ), California historical documents, city directories that cover everything from who Crenshaw was to the slogans of California cities. All these materials are available at the Los Angeles Public and many of them are available electronically from this site.