W3C has published an early draft of HTML 5 on its website.
Why the Community Wants HTML 5
Engineers, designers, marketing departments, and users have learned much about the Web as a medium since HTML 4 was first published in December 1997. Web sites reflect this progress: no longer static page collections, they are now media-rich communities that leverage participation and evolve dynamically to better meet customer needs. Ajax and related innovations have propelled demands for a new standard that allows people to create Web applications that interoperate across desktop and mobile platforms.
W3C launched the HTML Working Group in March 2007 as a forum for building consensus around the new standard. The group has already published a set of HTML design principles, which include: ensuring support for existing content, codifying widespread practice, separating concerns (markup from presentation), and enabling universal access. These principles help guide the group's decision-making.
What's New in HTML 5
Some of the most interesting new features for authors are APIs for drawing two-dimensional graphics, embedding and controlling audio and video content, maintaining persistent client-side data storage, and for enabling users to edit documents and parts of documents interactively. Other features make it easier to represent familiar page elements, including