California voters recently voted to change their state constitution to prohibit same sex marriage. That ballot question is known as "proposition 8".

According to googleblog, google has submitted an amicus brief to the courts opposing that change.

prop 8 wiki: http://en.wikipedia.org/wiki/California_Proposition_8_(2008)

amicus brief (pdf): http://www.nclrights.org/amicigoogle

googleblog: http://googleblog.blogspot.com/2009/01/supporting-equality.html

slashdot: http://tech.slashdot.org/article.pl?sid=09/01/16/159221

Correction:
The brief was from Google, Levi Strauss, H5, and the S.F. Chamber of Commerce.