Diff between Blueray and HD-DVD?

This will answer all of your questions...

http://en.wikipedia.org/wiki/HD_DVD

http://en.wikipedia.org/wiki/Blu-ray_Disc

I am putting my money on HD-DVD. Sony has had a terrible record with their attempts to push their formats (perhaps you remember beta). I think that the fact microsoft is backing HD-DVD is huge since PCs are being integrated into media systems more and more these days. I believe HD-DVD will allow you to copy the content onto your computer, this is what Microsoft wanted any why they are in the HD-DVD camp. With Blueray i do not think this is a possibility. Other than this i don't think is really anything to seperate the two formats. They are very similiar in data transfer and storage capacity. If you are thinking of buying one i would suggest waiting. If you do not want to wait I suggest HD-DVD. But remember to even get the full benefit of these discs you will need an HD TV that is able output in 1080P only the most recent TVs can natively support this.

EDIT(reply to below answer):

NO, blueray and HD-DVD are competing formats of high-density optical storage (bigger cd's essentialy). HD-DVD is led by Toshiba and Blueray by sony. They each have their own consortium of tech companies and movie studios behind them. Either someone will win this war and the other become obsolete or someone will design a player compatible with both formats (like dvd+r and dvd-r which used to need completely different hardware). They obtain this higher density by using a different wavelength of light, hence the name blueray. Both have their own discs and players.

blu-ray is the dvd record u burn on it can store more information HD-dvd is just a connection

more bs to confuse you and make you buy expensive equipment you dont need