Scheduled to launch on April 21, the World Digital Library "will make available on the Internet, free of charge and in multilingual format, significant primary materials from cultures around the world, including manuscripts, maps, rare books, musical scores, recordings, films, prints, photographs, architectural drawings, and other significant cultural materials."
APRIL 23 UPDATE: Well, the site has launched, and it looks amazingly great. I tested it out with a random search for "Nepal," and found An Account of the Kingdom of Nepal, published in 1811. You can read it on the World Digital Library site for free. How cool is that?