at least the first is hdr...i think the second on is some kind of 'makeraysbehindobjects' shader :S

It's postprocessing. you have to pass the position of the sun and then you can calculate the rays by doing lookups towards sun direction.

But i didn't see such a shader around here and i'm too lazy and busy to write such. I suppose it would be pretty slow btw because you have to do a lot of lookups