Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Well you can check if the backlight/LCD or the video card died; just plug in an external monitor and see if it works; if you don't have an external your only shot is to check out the Apple Store.
 
I just got mine back from the Apple service centre. They had to replace the logic board. This problem looks to be spreading. I would get it to your nearest Apple service place soon.

I could connect to mine by using screen sharing from my old iMac G5. It worked fine just no screen.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.