looks like some bloom mixed with some dynamic volumetric lighting. not sure that you're going to find a good realtime solutions for this that are that accurate, you best bet is to do some tweaking with bloom or hdr instead.
The easiest way to realize it is just to make everything but the sky black, use a radial blur on the image with the sun as center and add it to the ordinary rendered view. The only problem you will have to face with is that the sky will get too bright, but it shouldn´t be that hard to also solve that problem...
On the youtube video (orig. post) the author mentions it is a demo from his code in the lastest (or next?) GPU Gems book. Might be worth picking up if you're really interested.
