Yesterday the third IE9 Platform preview got released. This release includes support for the HTML5 <audio>, <video>, and <canvas> elements, the Web Open Font Format (WOFF), and many other new and improved capabilities.
The platform preview installs side by side with Internet Explorer 8 so that you can try it without replacing the full version of Internet Explorer that comes with Windows.
This third release of the Internet Explorer 9 Platform Preview will install over the prior versions. There is no need to uninstall the earlier builds before installing the third. You’ll also find more information on what’s included in this release of the Platform Preview in the Release Notes, including known and resolved issues.
You can download it here.