Find Archival Collections and Primary Sources guide from UC Berkeley.  ”[The UC Berkeley] Archives collect original unpublished, historical and contemporary material. Primary sources include manuscripts, diaries, letters, rare books, historical photographs, first-hand accounts or documentary sources on a subject, person, event or issue.”

Part of the UCB Digital Library project.  Provides links to other digital projects such as:  American Heritage Virtual Archive, California Heritage Collection, Free Speech Movement Collections, Japanese American Relocation Digital Archive, and the Museums in the Online Archive of California.