Atmospheric Flows: sediment transport and sedimentary structures
Aeolian Processes on Mars from the High Resolution Imaging Science Experiment (HiRISE) at the University of Arizona. Hundreds of beautiful images (includes Dunes).
Great Sand Dunes Formation Animation from the National Parks Service provides a quick geologic history of the formation of the sediment source, basin formation, deposition, and current dune locations. Additional dune type photographs and animations of those dunes found in Great Sand Dunes National Park.
Dune airflow from Jim Elder of Ottowa, Canada makes airflow visible around a dune by erecting streamers across the dune. An eddy of air is visible on the leeside of the dune, having implications for the bedform development. He also provides an animation and video of the sand movement associated with a leeside eddy.
Sand Dune Photographs by Marli Miller, University of Oregon. Stunning photographs of Sand Dunes. Search Miller's Earth Science Photography Page (more info) for more images.