I've been staying up past my bedtime just to surf the web to figure it out. So, what _is_ the name of the electronic song from the 1st half of the trailer?

I don't suppose you could say which trailer? There were three or four, each with music from different sources. At one point, Neil answered on his blog what 2 or 3 of the sources were, so the neilgaiman.com (not the board, the main site) search function might help you out

the 1 on the mirrormask site. the one that says something like "the other side of fate" and "this is my dream...the charm's a...mirrormask"

I don't think this is it. There were at least three trailers. One had music from the film, but that's not the one you asked about. One is answered in the quote below. Unfortunately, I think the one on the site might be the third one, and I'd have to really dig around a bit to find the answer (if it's out there - It appears I misremembered how many were named by Neil)
The teaser was, I think, the one that failed to mention Dave McKean
link

quote:

When the first MirrorMask Teaser went up, we mentioned that the music wasn't from the movie, and people started to ask write in to ask where it was from and who did it. And I said I'd try to find out.

So for everyone who was wondering, Michael Polis at Hensons tells me it was by a composer named Fletcher Beasley. And a quick google gives a website at http://www.beatrevolution.com/ for the curious.

does anybody knows which song it is? because i still can't find it

quote:

Originally posted by ProbablyMe:
does anybody knows which song it is? because i still can't find it

It's "C the Rainbow" by DJ Kambo. More info here.