Jerry Brown now leads Meg Whitman in two different polls, both released on July 28, 2010. The first poll, released by Public Policy Polling, shows Jerry Brown leading Meg Whitman 46%-40%. The second poll, released the same day by the Public Policy Institute of California, shows Jerry Brown ahead of Meg Whitman 37%-34%.
Here are the links to both polls (Requires Adobe PDF Reader):
Public Policy Polling Survey:
Public Policy Institute of California Statewide Survey (pg. 32, q. 44):