pgDay San Jose will be a full day of PostgreSQL sessions the day before O'Reilly Open Source Conference starts, followed by a party.
Full schedule and details for the pgDay are on the pgDay wiki page.
Ride-sharing board is here: http://wiki.postgresql.org/wiki/Ride_Board_PGDAY_SJ_2009
RSVP here to Register for the event. You must RSVP separately for the party, if you are attending that as well.
pgDaySJ is sponsored by:
Facilities Sponsor: O'Reilly and Associates
Platinum Sponsor: EnterpriseDB
Break Sponsor: Aster Data
For those unable to attend, there will be video of the entire event, and possibly streaming coverage.