Good news - Proposition 8 is losing 42-51 at this point.
According to a Field poll (available to subscribers only, but I have a copy) dated July 18th, the gay marriage ban is doing much worse than the last time it was on the ballot. Most demographics are distinctly against Prop 8.
In fact, it's easier to name the smaller number of demographics that are for Prop 8 - Republicans, evangelicals, Protestants, Latinos, and rural areas of the northern 2/3 of the state. Even Southern California, led by Los Angeles, is trending against Prop 8, including Orange County and Inland Empire - though barely. (Of course, the strongest opposition is in the Bay Area.)
Also of interest is the fact that independents are more against Prop 8 (66%) than Democrats (63%). Maybe this has to do with the fact that many of the Democrats are Latinos and other socially conservative immigrant groups that are less likely to oppose Prop 8.
So far, this is promising, but it is important for Equality for All to keep up its fight even more, so that even the conservative immigrants can be won over. The Yes campaign is well-funded, and can run slick ads to pull out a nasty surprise, especially among these immigrant demographics.
Update: Sacramento Bee has detailed data from the poll.