Sounds like the inverter.
When I used to fix flat panel lcd monitors usually we would replace the inverter and presto the screen would be back on and you are able to see the the display again.
I guess your macbook is out of warranty or do you have an extended warranty.
If it's still under warranty send it in for repair. If it's out of warranty change it yourself if you know how.
Here is a link below on you tube to change the inverter.http://www.youtube.com/results?search_query=change+inverter+on+macbook+screen&oq=change+inverter+on+macbook+screen&gs_l=youtube.3...1223.19602.0.204126.96.36.199.0.0.0.1701.12592.9j6j4j1j3j4j3j2j1.33.0...0.0.3dl6KeYjteQ
Have fun. Just don't break anything.