Will be a razor thin vote.
Nate Silver at 538 gives 1/3 odds on passage.
Heres the link to his blog, excellent site BTW.
http://www.fivethirtyeight.com/2009/05/whip-count-gay-marraige-faces-uphill.html (http://www.fivethirtyeight.com/2009/05/whip-count-gay-marraige-faces-uphill.html)