This is basically a web-browser, inside XNA, drawing over-top of anything being drawn by XNA. You'll have to write your own html pages to make it look the way you want, but here are some great resources:
Awesomium.com - What you're looking at
jQuery.com - Great JavaScript
gpwiki.org - Game development resources
gamedev.stackexchange.com/ - A great place to ask your gamedev questions
Google - So that you can experiment with Awesomium and see what it can do!

Here is a data placeholder that you shouldn't see if you're in Awesomium

Click to exit Awesomium