Q: How can I get advanced access to Internet Explorer's new features and developer tools?
A: Microsoft has released the Internet Explorer Developer Channel, which is a separate version of Internet Explorer that showcases new and upcoming technologies and standards that you can start using and developing against. You can install the Developer Channel alongside a standard Internet Explorer installation. (Microsoft currently uses App-V to deliver the Developer Channel, in order to provide isolation.)
Microsoft's IEBlog discusses some of the Developer Channel's key features. It's important to read the release notes and FAQs, because some features aren't enabled by default (e.g., WebDriver, to maximize your security). The FAQs explain how to enable WebDriver and other capabilities.