Via MySpace, here's the trailer for 11th Hour with a spoken intro by Leonardo. According to IMDB, the film will be released in the USA on August 17th. Check out the official 11th Hour website.
See also: ::Leonardo DiCaprio's Latest Eco-project: Global Warming Documentary, ::Leo DiCaprio: "I Took a Train Across the Atlantic"
Via ::Hugg (thanks Linton!)