This is only a preliminary design, but these pics are what the Xbox 360 team are looking at for integrating the HD DVD with your internal DVD drive in the UI. Looks pretty straightforward. Similar to the design that the current DVD has.
We wonder if we're going to be able to play games in the HD DVD drive as well. Keeping two games queued up for easy switching would mean less trips to the 360. Yes, we're lazy.
More on the HD-DVD player from Major Nelson [Gamerscoreblog]