This from the Barak Obama Campaign folks… a little primer on voting:
Polls are open from 7:00 a.m. to at least 8:00 p.m. Anyone in line at the time the polls close is allowed to vote.
Voters have the right to cast a provisional ballot even if their name is not listed on the voting rolls. If a voter is at the wrong polling location and has time to get to the correct polling location before polls close at 8:00 p.m., they should go to the correct one and vote with a regular ballot instead of voting with a provisional ballot at the wrong location.
If you declined to select a political party when you registered to vote, you can still vote for Barack Obama if you request a Democratic ballot from the poll worker. Make sure you mark “Democratic” in the appropriate space or the vote might not be counted.
Voters have the right to return a completed vote-by-mail ballot to any precinct in their county.
If you have any difficulties, you can call the California Obama Election Protection Hotline:
o LOS ANGELES: (310) 801-9546 or (310) 779-0816
o SAN FRANCISCO/BAY AREA: (510) 520-5025
o OAKLAND/EAST BAY: (415) 606-6043
o SAN DIEGO: (619) 770-7105