Arcane University:CrazyBump for Skyrim
CrazyBump is one of the many automated texturing tools, others are included into modern 3d software as modules. It can also be used to overhaul existing or algorythm-created textures. Usually it gives out dds or png files, however its best to do some post processing in Gimp or Photoshop to adjust the 5 channel PBR layers to the 2 or 3 channels being used in Skyrims texture sets.
You can find details of the export formate and necessary settings on the page Arcane_University:DDS_Data_Format.