The beta release of Internet Explorer 9 launched on Wednesday of this week. If you're a developer this means a number of things:
First things first: where do you get the IE 9 beta and what is new?
After you have the beta, you can load up your site and see how it looks. If you have a complex site, you might want to start looking through the IE6 to IE8 compatibility guide that we published last week. This guide contains lots of helpful suggestions for tools, an explanation of developer features in Internet Explorer, and testing recommendations.
If you're interested in taking full advantage of the various browser features of IE9, you should take some time to go through the revamped IE developer center. This portal includes a comprehensive list of the feature of Internet Explorer 9 that are relevant for developers and also has a collection of additional resources that you can use for further research.