HTML 5 - A Choice for Web 2.0+

HTML 5 is the latest revision of the HTML standard and has been structured to improve support for 'Web 2.0' capabilities of today's web. This includes support for the latest multimedia, apart from a number of new language constructs and improvements to continue enabling humans and computers to process.

Here's a comprehensive look into HTML v5.

How to build a html5 websites.v1

Google html5 Tutorial

A summary of some major differences between HTML v4.x and HTML 5, can be found here.