I am going to create an HD project to eventually author into an HD DVD (or Blue Ray). It is composed of large rez images. In the meantime I will drop that composition into a wide screen DV project (by scaling) to author into current DVDs.
I am not sure of the settings for the HD composition. I guess it would be 1920x1080. The pixel ratio seems to have to be square for an undistorted image...but this doesn't seem right.
I guess Windows Media will eventually be the way to render it out when the HD authoring systems and burners arrive. I don't seem to see HD settings for Windows Media in the Output Module, but then again I have AE 6.
There are no special settings required, just use the standard HD templates (720x1280 will be enough as most players will initially use this as a prefered format due to bandwidth constraints). To be on the safe side, try to work at 60 fps progressive, you can always derive al other versions from that. I doubt that either of the initial series of software and hardware will use Windows Media (or more properly VC 1). There are too many things still unclear and since Microsoft jumped aboard rather late, it's not going to be implemented too well, I think. Rely on H.264 or good old MPEG-II and plan with that in mind.