I saw a diary on this a few minutes ago, a voter who went Provisional and was almost certainly a victim of this. CBS news on the radio is also talking about this, which means it must be a fairly common issue.
1. If you have your sample ballot GO WHERE IT SAYS TO GO, not where you always have gone.
2. If you have an absentee ballot, any polling location IN YOUR COUNTY is good.
3. If you don't have the sample ballot and are not on the rolls wherever you went, go to this website for your county commisioner's phone#. They'll tell you where to go (it is all done by county in CA). There is a very good chance the polling place will know the number, ask them before going online. Or go to step 4 and use the statewide helpline.
4. From the URL in #3 "Not sure what county you live in? Simply enter your zip code with the U.S. Census Bureau or call our Voter Assistance Hotline at (800) 345-VOTE."
5. A provisional ballot should be only if the alternative is you won't vote at all (cause you have to get back to work etc, instead of making the phone call and going to your real polling spot)
Hope this helps. Happy voting!