Several Microsoft employees are providing excellent information on HD DVD, especially HDi, on their blogs. This section will provide links to some of the best, along with occasional comments. In fact, some should probably be considered essential reading for anyone intending to work with Advanced Content.
Peter Torr's blog - This fantastic blog contains a wealth of information on HDi, including discussions of the Microsoft HDi examples, links to useful authoring tools and advanced scripting examples - play Space Invaders on an HD DVD player !
Links to useful posts on Peter's blog ( remember they called it iHD in the early days ) - these make a pretty good starter course, in fact:
Amy Dullard's Blog - Another great resource for getting up to speed on HDi development, including summaries of available tools and discussions of creating ACA files:
Andy Pennell's Blog - Less technical stuff but still some interesting posts.