The blue laser has a shorter wave than the red allowing for a far more precise reading, but as promising as it is blu-ray is not over the line yet...just because it's superior to the HD-DVD it also requires complete factory re-tooling whereas the (red) HD-DVD requires only partial re-tool (not the only reason), I read this format war was likley to be decided by Hollywood but last year Disney came out and will be backing Blu-Ray while Warner (?) or some other major studio(s) would be backing HD-DVD.
If anyone is interested to learn more or see a few players blu-ray.com has all the info you could want.