IMDb reports that Gus Van Sant's next film, Milk will be out in the U.S. in December 2008. It will tell the story of Harvey Milk, "the first openly gay man elected to any substantial political office in the history of the planet" (according to Time-magazine), who was murdered, along with then-Mayor of San Fransisco, George Moscone, by their recently-resigned colleague Dan White.
Dan White only served seven years and some months for this double murder, and his trial became infamous for the Twinkie defense; despite having always been a health-nut, White had recently taken up eating Twinkies and drinking Coca-Cola, and White's attorney claimed he had murdered Harvey Milk and George Moscone because the junk food had worsened his depressed mental state.
If you have the time, I highly recommend the Academy Award-winning documentary The Times of Harvey Milk, which you can watch in parts on YouTube. It features a lot of archive footage of Milk, speaks with his campaign workers and it gives an insight into the emancipation of gay men and women in San Fransisco in the 1970s.