In this post by Saijo George, you will find a video demo on some new features on IE9 for Windows Phone.
Source: 1800PocketPC
The video shows off Internet Explorer 9:
1. style divs and border radius implementation of animated IE9 logo
2. Scalable Vector Graphics (SVG) support : read zoom in and the images will still look sharp
3. the address bar is moved to the bottom ( dont know about that one .. what do you guys think )
4. Landscape demo of HTML5 WebApp from IMDb ( or you can just get the super cool WP7 IMDb app )