Basically, Blu-Ray and HD-DVD is the future of DVD's, due to size limitations in todays DVD5's and DVD9's (aka Dual-layer).
For those that care,
Blu-Ray and
HD-DVD info without prorietor bias. There you can check out size limits of each format, and current industry support (VERY important topic on this debate).
Diesel, WinDVD8 can play it according to forums, but it only retails in
Japan afaik, and is not out on the scene as far as I've checked. I
think it requires hdcp gpu's.