Here is a link to the State of California/Department of Corrections/Folsom Prison, which has a little info on Folsom and it's history.
http://www.cdcr.ca.gov/Facilities_Locator/FSP.html
This is a link to the Folsom Prison Museum. The Museum is located on the grounds of Folsom Prison at 300 Prison Road, Folsom, California, 95670. The Museum is managed by retired Lt. Jim Brown. Jim has wrote a few books on Folsom Prison. You can find them on the Museum web site or inside the museum.
http://www.folsomprisonmuseum.org/