Over at the DVD Forums, its been reported that Sony are releasing FAFDM on Blu Ray this March/April. Anyone tempted to buy
I forgot about this. I haven't heard any more news but will chase it up.
Blue Ray is another form of HD DVD in which, like the name says, a blue ray is used to read info off the discs.
I believe Blue Ray disc's can hold more data. Thats pretty much the difference.
If you mean in picture terms then the quality will be much better, there will also be more space for soundtracks and certain soundtracks will be enhanced for HD format (Dolby Digital HD for instance). Mainly more room on the disc itself.