Atmospheric scattering

I really love the sun and atmosphere panel in the blender engine. However, cycles does not have the same. Does anyone know how to simulate the atmosphere panel with nodes? Specifically: Sun, Distance, Inscattering, Extinction.

I am familiar with the Map Value method of creating fog - this is really great. However - the Atmosphere panel does more - sun, distance, inscattering, and extinction. Does anyone know how to simulate all of these features in nodes?