Atmospheric Optics - Features pictures of and information about atmospheric optics formed by light playing on water drops, dust, or ice crystals in the atmosphere.
Light and Optics: Online Meteorology Guide - Looks at the effects of sunlight (or moonlight) that is either absorbed, reflected, scattered, refracted or diffracted by atmospheric particles or air molecules.
Meteoptic - Mailing list for amateurs and scientists interested in atmospheric optical phenomena.