Matt points to a Pew survey showing that the pre-1946 generation now has more liberal views on interracial marriage than either baby boomers or Gen-Xers did twenty years ago. In other words, the liberalization of attitudes on that issue isn't just a matter of old people with right-wing views passing away, and a more accepting generation replacing them. It's a matter of time eroding away the prejudices even of the old.
It's a nice statistic too for those of us who want to see America respect gay people's right to marry. The psychological roots of the prejudices inspiring the conservative position on both issues are fairly similar, even if antigay prejudice comes with a clearer theological cover story. If time can wear away one prejudice, it can wear away the other, and I'm always happy to see the two prejudices linked in public discourse. I'm not usually one to push the "Obama as transformational leader" meme, but if he were interested in doing so, he could make some powerful points in favor of full-fledged gay marriage. He is, after all, the child of a marriage once forbidden in some places by prejudice, and he could powerfully link the issues together.
