don't know how much help i'l be able to get here but...
im trying to figure out a good way to do this effect and i really don't know what to call it which is making it harder to find something to start with.
anyway its kinda like a window would be really overblown but its not just in camera...like your creating a light for it in post...
k i cant explain it, its used in this video at 11:20 and onwards, if thats to far in for you just pause it let it load and skip to it if you think you might be able to help. its a very well done short though so watch if you have the time.
http://vimeo.com/3568757